I 


IS  HIS  GREATEST 


^  / 


LECTURES  ON  VENTILATION 


BEING  A  COURSE  DELIVERED  IN  TH* 


FRANKLIN  INSTITUTE, 


OF   PHILADELPHIA, 


DURING    THE    WINTER    OF    1866-67, 


BY  LEWIS  W.  LEEDS, 

OBNT  07  THK  QUARTERMASTER-GENERAL,  FOR  THE  VENTILATION  OP  GOVERNMENT  HOSPITAM 

DURING  THE  WAR;  AND  CONSULTING  ENGINEER  OF  VENTILATION  AND  HEATING 
FOR  THE  U.  S.  TREASURY  DEPARTMENT. 


Man's  own  breath  is  his  greatest  enemy. 


NEW  YORK: 

JOHN  WILEY  &  SON,  PUBLISHEKS, 

2  CLOTTON  HALL,  ASTOB  PLACE. 

1869. 


Entered  according  to  Act  of  Congress,  in  the  year  1868,  by 

LEWIS  W.  LEEDS, 

i  the  Clerk's  Office  of  the  District  Court  of  the  United  States  for  the  Southern  District 
of  New  York. 


NEW  YORK  PRINTING  COMPANY, 

81,  83,  and  85  Centre  Street, 

NEW  YORK. 


PEEFACE. 


THESE  Lectures  were  not  originally  written  with  any  view  to  their  pub  i- 
cation  ;  but  as  they  were  afterwards  requested  for  publication  in  the  Jour- 
nal of  the  Franklin  Institute,  and  there  attracted  very  favorable  notice,  I 
believed  the  rapidly  increasing  interest  in  the  subject  of  ventilation  would 
enable  the  publishers  to  sell  a  sufficient  number  to  pay  the  expense  of  their 
publication ;  and,  if  so,  that  this  very  spirit  of  inquiry  which  would  lead 
to  the  perusal  of  even  so  small  a  work,  might  be  one.  step  forward  towards 
that  much-needed  more  general  education  on  this  important  subject. 

It  was  not  my  desire  to  give  an  elaborate  treatise  on  the  subject  of 
ventilation.  I  believed  a  few  general  principles,  illustrated  in  a  familiar 
way,  would  be  much  more  likely  to  be  read ;  and,  I  hoped,  would  act  as 
seed-grain  in  commencing  the  growth  of  an  inquiry  which,  when  once  started 
in  the  right  direction,  would  soon  discover  the  condition  of  the  air  we 
breathe  to  be  of  so  much  importance  that  the  investigation  would  be  eagerly 

pursued. 

L.W.  L. 


CONTENTS. 


LECTUKE  I. 

Philadelphia  a  healthy  city— Owing  to  the  superior  ventilation  of  its  houses— But 
the  theory  of  ventilation  still  imperfectly  understood — About  forty  per  cent, 
of  all  deaths  due  to  foul  air — The  death  rate  for  1865 — Expense  of  unnecessary 
sickness — In  London — In  Massachusetts — In  New  York — In  Philadelphia — 
Consumption  the  result  of  breathing  impure  air — Entirely  preventable — • 
Infantile  mortality — lieport  on  warming  and  ventilating  the  Capitol — Copies 
of  various  tables  therefrom — Carbonic  acid  taken  as  the  tes>t,  but  not  infallible* 
— The  uniform  purity  of  the  external  atmosphere — Illustrated  by  the  city  of 
Manchester — Overflowed  lands  unhealthy — Air  of  Paris,  London  and  other 
cities — Carbonic  acid  in  houses — Here  we  find  the  curse  of  foul  air — Our  own 
breath  is  our  greatest  enemy — Scavengers  more  healthy  than  factory  operatives 
— Wonderful  cures  of  consumption  by  placing  the  patients  in  cow  stables — 
City  buildings  prevent  ventilation,  consequently  are  unhealthy — The  air  fmoi 
the  filthiest  street  more  wholesome  than  close  bed-room  air — Unfortunate 
prejudice  against  night  air — Dr  Franklin's  opinion  of  night  air — Compared 
with  the  instructions  of  the  Board  of  Health,  1866— Sleeping  with  open 
windows — Fire  not  objectionable — A  small  room  ventilated  is  better  than  a 
large  room  not  ventilated — Illustration — Fresh  air  at  night  prevents  cholera 
— Illustrated  by  New  York  workhouse — Dr.  Hamilton's  report — Night  air  just 
as  healthy  as  day  air — Candle  extinguished  by  the  breath — The  breath  falls 
instead  of  rises — Children  near  the  floor  killed  first — Physicians'  certificates 
do  not  state  "  killed  by  foul  air  " — Open  fire-places  are  excellent  ventilators — 
All  fire-boards  should  be  used  for  kindling  wood — Illustration  showing  when 
ceiling  ventilation  is  necessary  • PAGE  3 

LECTUKE  II. 

The  effect  produced  by  heat  upon  the  movements  of  air — Air  a  real  substance — 
Exerts  a  pressure  of  fifteen  tons  on  an  ordinary  sized  man — It  cannot  be  moved 
without  the  expanditure  of  power — The  sun's  rays  the  great  moving  power  — 
They  pass  through  the  forty-five  miles  of  atmosphere  without  heating  it,  and 
heat  the  solid  substances  of  the  earth's  surface— Experiments  showing  the  effect 
of  radiant  heat  and  reflected  heat — The  air  of  the  room  not  pure  and  dry — The 
ordinary  moisture  absorbs  from  fifty  to  seventy  times  as  much  as  the  air — 
Many  gases  absorb  much  more— The  moisture  in  the  air  the  great  regulator 
of  heat — Air  is  heated  by  coming  in  immediate  contact  with  hotter  substances 
— Impossibility  of  any  air  remaining  at  rest — The  practical  application  of  these 
principles— The  open  fire  acts  like  the  sun,  heating  by  radiation  only — Probable 
electric  or  ozonio  change  in  furnace-heated  air — The  stove  heats  both  by 
radiation  and  circulation— The  stove  nor  the  open  fire  not  suitable  for  large 
crowded  rooms — Circulating  warmed  air  best — Erroneous  views  in  regard  to 
ventilation — Experiments  with  liquids  of  different  densities — When  warming 


and  ventilating  by  circulating  air,  the  escape  for  the  used  air  should  oe  from 
the  bottom  of  the  room — But  when  ventilating  with  cooler  air  the  escape  should 
be  from  the  top  of  the  room — Windows  should  lower  from  the  top  and  flues 
open  at  the  bottom  of  the  room — The  fashionable  system  of  heating  by  direct 
radiation,  without  any  fresh  air,  very  objectionable  .  .  .  PAGE  18 

LECTURE  III. 

One  breath  of  impure  air  shortens  our  life — Difficulty  of  getting  pure  air  to  breatho 
in  houses  and  cars — Foul  air  in  steam  cars — "Want  of  the  proper  knowledge 
regarding  ventilation  among  all  classes — Want  of  ventilation  in  this  lecture 
room — Want  of  ventilation  in  the  Cooper  Institute,  and  in  many  other  new 
and  splendid  buildings — Street  cars  very  foul — My  own  chamber  fully  venti- 
lated—I  have  no  new  patent  idea,  sufficient  for  all  time  without  further  thought 
— Constantly  varying  conditions  require  separate  intelligent  thought  and  action 
—The  air  moves  horizontally  in  summer— Flues  are  then  of  no  account— We 
must  depend  on  open  doors  and  windows — How  to  ventilate  a  sick  room  in  the 
morning — The  same  in  the  evening — Windows  should  always  lower  from  the 
top — To  make  air  move  in  the  summer  is  the  great  desideratum — When  in 
motion  the  cold  air  falls  and  warm  air  rises ;  when  at  rest,  it  is  arranged  in 
horizontal  layers,  according  to  temperature — A  flue  is  simply  a  passage  for  air 
of  different  temperatures — Experiments  with  flues  of  different  temperatures — 
Expansion  of  air  by  heat — Weight  required  to  keep  it  from  expanding — Heat- 
ing air  weakens  it  instead  of  giving  it  power — Experiments  showing  draughts 
by  lighted  candles — Ventilation  of  churches — Illustrations  not  exaggerated — 
Examination  of  church  in  neighborhood — Fresh  air  taken  from  foul  cellar — 
No  fresh  air  supplied  to  churches  used  as  hospitals  in  Washington — Depend- 
ing on  a  sham  ventilator  painted  on  the  solid  wall — Foul  air  in  Philadelphia 
schools — New  York  public  schools — Many  of  the  ventilators  perfect  shams — 
Covered  up  air-tight  by  the  capping  stones — Importance  of  the  evaporation  of 
water — A  strong  fire  in  basement  will  draw  gas  out  of  second  story  stove — A 
strong  fire  up  stairs  will  draw  foul  gases  from  untrapped  sewers — A  very 
healthy  location  may  thus  be  made  very  unhealthy — Drs.  Palmer,  Ford  and 
Earle's  report  of  epidemic  at  Maple  Wood  Institute — An  arrangement  for 
ventilation  that  ought  to  be  in  every  house — Flues  generally  too  small,  especi- 
ally in  Philadelphia — Very  large  ones  put  in  government  hospitals,  which 
proved  thoroughly  efficient — The  leading  points  in  regard  to  heating — The 
fresh  air  must  be  warmed  before  entering  in  winter — A  hot  water  furnace 
requires  additional  moisture — Heating  by  steam — Steam-pipes  ought  to  be  laid 
through  the  street  the  same  as  gas  and  water — Two-thirds  of  heating  surface 
should  be  for  heating  the  fresh  air  and  one  third  for  direct  radiation— Forty 
pounds  of  water  required  to  be  evaporated  every  minute  for  U.  S.  Senate 
Chamber — All  stoves  should  have  fresh-air  boxes — Dampers  in  fresh  air-boxes 
not  good — Experience  has  fully  demonstrated  that  careful  attention  to  these 
things  will  be  amply  rewarded  by  increased  health,  strength,  happiness  and 
longevity PAGK  31 

Article  relating  to  the'  Grand  Prize  awarded  to  Hospital  Ventilation  and  other 
Sanitary  arrangements,  Paris  Exhibition PAGE  51 


LECTURES  ON  VENTILATION. 


LECTUKE  I. 

PHILADELPHIA  is  one  of  the  healthiest  cities  in  the  United  States, 
and,  in  proportion  to  the  number  of  its  inhabitants,  few  more  healthy 
cities  exist  in  the  world. 

This  is  not  owing  especially  to  its  more  salubrious  situation,  but 
should  be  attributed,  in  a  great  measure,  to  the  accidental  superiority 
of  the  ventilation  of  a  large  proportion  of  its  dwelling-houses. 

Notwithstanding  this  comparative  excellence,  tho  theory  of  ventila- 
tion is  not  so  thoroughly  understood,  nor  13  the  practice  so  perfect, 
even  in  this  city,  that  no  advantage  can  be  gained  by  further  know- 
ledge upon  the  subject. 

Far  from  it.  From  the  very  best  information  we  can  command,  and 
with  the  most  accurate  statistics  at  our  disposal,  we  are  forced  to  the 
conclusion  that  about  forty  per  cent,  of  all  the  deaths  that  are  con- 
stantly occurring  are  due  to  the  influence  of  foul  air. 

The  Registrar  of  Records  of  New  York  gives  nearly  half  the  deaths 
in  that  city  as  resulting  from  this  cause. 

The  deaths  in  this  city  for  1865,  according  to  the  report  of  the 
Board  of  Health,  were  seventeen  thousand  one  hundred  and  sixty- 
nine  ;  the  average  age  of  those  who  died  was  between  twenty-three  and 
twenty-four  years.  It  ought  to  have  been  twice  that,  as  shown  by  some 
districts  in  the  city  and  also  in  the  country,  where  the  houses  are  so 
arranged  that  they  frequently  have  good  ventilation. 

Taking  the  deaths  caused  by  foul  air  at  a  very  low  estimate,  say 
forty  per  cent,  of  the  whole,  (the  per  centage  from  that  cause  is  not 
so  great  as  in  New  York,)  we  have  six  thousand  eight  hundred  and 
sixty-eight  deaths  in  this  city,  caused  alone  by  impure  air,  in  one  year. 

It  is  estimated  by  physicians  that  there  are  from  twenty-five  to  thirty 
days  of  sickness  to  every  death  occurring;  there  would  therefore  be 
something  like  two  hundred  thousand  days  of  sickness  annually  as  an 
effect  of  foul  air. 

We  all  know  how  very  expensive  sickness  is,  but  few  persons  realize 


the  enormous  aggregate  expense  of  unnecessary  sickness  in  a  city  like 
Philadelphia.* 

This  subject  has  awakened  much  interest  in  Europe  of  late  years, 
and  has  led  to  the  expenditure  of  immense  sums  of  money,  for  the  pur- 
pose of  improving  the  sanitary  condition  of  its  cities. 

Dr.  Hutchinson  estimated  the  loss  to  the  city  of  London,  growing 
out  of  preventable  deaths  and  sickness,  at  twenty  millions  of  dollars 
annually,  and  Mr.  Mansfield  estimates  the  loss  from  this  cause  to  the 
United  Kingdom  at  two  hundred  and  fifty  millions  of  dollars. 

In  the  single  State  of  Massachusetts,  an  estimate  exhibits  an  annual 
loss  of  over  sixty  millions  of  dollars  by  the  premature  death  of  persons 
over  fifteen  years  of  age. 

It  is  estimated  that  a  few  only  of  the  principal  items  of  expense  in- 
curred by  preventable  sickness  in  the  city  of  New  York  amount-  to 
over  five  millions  of  dollars  annually. 

And  if  it  is  thought  that  Philadelphia  is  exempt  from  such  enormous 
unnecessary  expense,  just  glance  at  the  report  of  the  Board  of  Health 
for  last  year,  and  see  how  the  deaths  from  disease  of  the  lungs  largely 
exceed  those  from  any  other  disease. 

Consumption  is  almost  entirely  the  result  of  breathing  impure  air, — 
it  is  as  preventable  by  the  exclusive  use  of  pure  air  as  mania  a  potuor 
drunkenness  is  by  the  exclusive  use  of  pure  water.  And  see,  too,  what 
slaughter  among  the  innocents — over  twenty-five  per  cent,  of  the  whole 
deaths  were  under  one  year  of  age. 

The  infantile  mortality  is  by  many  considered  the  most  delicate 
sanitary  test.  But  why  does  such  an  intelligent  community  as  this 
so  neglect  its  own  interest? 

They  have  listened  to  and  satisfied  the  first  imperative  demands  of 
nature — shelter  from  the  elements  and  warmth, — and  in  doing  this  they 
have  not  brought  into  use  that  much  higher  order  of  intellect  which 
can  alone  teach  them  how  to  supply,  in  connection  with  an  agreeable 
warmth,  an  abundance  of  pure  air  in  their  otherwise  air-tight  houses. 

I  have  been  much  interested  in  examining  a  large  collection  of  tables 
of  the  analysis  of  air,  which  accompany  a 'report  to  Congress,  on 
"  Warming  and  Ventilating  the  Capitol,"  prepared  by  Thomas  U. 
Walter,  Professor  Henry  and  Dr.  Wethcrill.  These  tables  were  made 
by  me«i  of  various  nations,  giving  the  results  of  their  analysis  of  air 


*  I  mean  merely  pecuniarily — in  dollars  and  cents ; — the  cost  in  physical  pain  and 
mental  anxiety,  of  course,  cannot  t>s  computed  in  dollars  and  cents. 


taken  from  all  manner  of  places,  from  great  elevations  on  the  moun- 
tains and  in  balloons,  from  the  valleys,  from  the  centre  of  the  ocean, 
and  from  the  middle  of  the  continent,  in  cities  and  in  the  country,  in 
winter  and  in  summer,  at  night  and  in  the  day,  and  also  the  compara- 
tive analyses  of  the  air  out  of  doors  and  in  houses.  Believing  that 
these  would  be  of  much  interest  and  assistance  to  us  in  the  investiga- 
tion of  the  subject  under  consideration,  I  have  had  copies  made  of 
some  of  the  most  interesting. 

These  give  the  per  centage  of  carbonic  acid  in  the  air  as  the  test  of 
the  amount  of  impurities  in  it. 

This  is  not  an  infallible  test  by  any  means — there  are  various  other 
causes  of  deterioration.  There  is  the  exhaustion  of  the  oxygen  con- 
stantly occurring  to  support  combustion  and  animal  life ;  there  are 
various  other  deleterious  products  of  combustion  and  respiration  be- 
sides carbonic  acid.  But,  as  carbonic  acid  is  always  found  in  certain 
known  proportions  in  pure  air,  and  is  always  formed  in  certain  known 
quantities  by  respiration  or  combustion,  it  is  considered  by  many  to 
give  a  very  fair  indication  of  the  condition  of  the  atmosphere  with 
reference  to  its  influence  on  animal  life  or  combustion. 

I  think  one  of  the  most  valuable  lessons  to  be  learned  by  the  study 
of  these  tables  is  the  uniform  purity  of  the  external  atmosphere  all 
over  the  world,  even  in  large  cities. 

This  is  strikingly  illustrated  in  the  case  of  the  analysis  of  the  air 
in  the  city  of  Manchester. 

We  have  nothing  in  this  country  like  that  city,  where  two  millions 
of  tons  of  coal  are  burned  annually,  the  smoke  from  which  fills  the  air 
and  stretches  like  a  black  cloud  far  into  the  country. 

Thus,added  to  the  five  hundred  tons  of  carbonic  acid  thrown  from 
the  lungs  of  its  animal  life' every  day,  are  many  times  that  amount, 
(some  two  thousand  tons,)  daily,  pouring  out  from  its  forest  of  factory 
chimneys. 

To  this  city  were  the  labors  of  the  "Health  of  Towns  Commission" 
first  directed,  to  see  if  they  could  not  find  in  the  air  of  its  streets  that 
mysterious  influence  that  has  caused  such  alarm  throughout  the  civil- 
ized world,  as  the  thoughtful  and  intelligent  sanitarian  sees  one-half 
of  all  his  fellow-citizens  hurried  to  untimely  graves. 

They  were  disappointed,  and  well  might  Dr.  Smith  exclaim,  after 
the  most  thorough  and  careful  investigations,  "How  insignificant  are 
the  works  of  art  in  contaminating  that  vast  ocean  of  air  that  is  con- 
stantly sweeping  over  the  surface  of  the  earth!"  But  do  not  be  dis- 


6 

couraged :  more  recent  investigations  have  discovered  the  whereabouts 
of  this  pestilential  breath. 

I  have  placed  the  table  of  Dr.  Angus  Smith's  analysis  of  the  air  of 
Manchester  at  the  head  of  the  list,  and  have  copied  it  complete,  because 
it  is  the  only  table  that  I  have  examined  of  the  analysis  of  the  air  of 
towns  in  Europe  or  North  America,  in  which  there  occurs  an  amount 
of  carbonic  acid  exceeding  ten  parts  in  ten  thousand. 

Here  we  see  three  such  cases  in  the  twenty-eight  experiments,  one 
ten,  one  twelve  and  one  fifteen. 

The  average  of  the  whole  is  also  greater  than  in  any  other  similar 
tables,  being  about  seven  and  a  half  parts  in  ten  thousand.  This  is 
certainly  quite  a  perceptible  contamination,  pure  air  containing  four 
or  four  and  a  half  parts  in  ten  thousand.  Yet  considerable  as  this 
appears  in  this  view,  the  additional  amount  of  carbonic  acid  is  only 
the  proportion  that  would  be  added  to  the  air,  if  unchanged,  of  a  room 
fifteen  feet  square  and  ten  feet  high,  by  a  father,  mother  and  three 
children,  with  a  gas-light,  in  seven  minutes. 

And  this,  probably,  is  the  highest  average  contamination  that  is 
produced  by  artificial  means  upon  the  air  of  any  city  in  the  world. 

There  are,  of  course,  great  natural  causes  which  affect  the  air  of 
whole  countries,  such  as  the  decomposition  of  great  masses  of  vege- 
table matter  similar  to  that  occurring  on  the  low  flat  lands  along  rivers, 
especially  where  they  overflow  their  banks,  like  the  Ohio  and  Missis- 
sippi. The  best  system  of  ventilation,  as  applicable  to  this  kind  of 
foul  air,  is  to  keep  as  far  out  of  its  reach  as  possible. 

The  other  tables  giving  the  analysis  of  the  air  of  London,  Paris, 
Madrid,  Geneva,  Bolton,  England,  at  different  elevations  on  the  moun- 
tains, on  the  Atlantic  Ocean,  Washington  City  and  various  other  places, 
are  interesting  only  because  they  show  so  great  a  uniformity  in  the 
carbonic  acid,  seldom  exceeding  six  parts  to  the  ten  thousand,  and  sel- 
dom under  four. 

But  now  let  us  look  upon  the  other  side  of  the  room.  Here  we  have 
tables  giving  the  "carbonic  acid  in  houses."  Here  we  will  find  very 
different  results.  But  the  first  is  a  green-house;  in  that  there  is  no 
trace  of  carbonic  acid  in  the  evening  and  scarcely  a  trace  in  the  morn- 
ing. Plants,  you  know,  absorb  the  carbonic  acid,  and  give  off  oxygen, 
while  animals  absorb  the  oxygen  and  give  off  carbonic  acid,  thus  keep- 
ing up  the  equilibrium  in  nature,  as  is  so  beautifully  shown  in  the  aqua- 
rium. Plants  are  generally  supposed  to  give  off  carbonic  acid  at  night, 
but  it  must  be  in  very  small  quantities. 


I  consider  them  very  conducive  to  health  in  a  living-room,  morally 
and  physically. 

But  this  want  of  carbonic  acid  does  not  last  long. 

The  next  is  M.  Dumas'  lecture-room.  At  commencement  of  lecture 
42'5,  and  at  close  of  lecture  67  parts  in  ten  thousand. 

Now,  I  think  we  are  on  the  right  track  for  discovering  that  myste- 
rious poison  that  has  carried  so  many  of  our  friends  to  their  graves, 
even  in  the  very  prime  of  life. 

Here  we  have  dormitories,  52;  do.,  37;  asylum,  17;  school-room, 
30;  do.,  56;  Chamber  of  Deputies,  16;  Opera  Comiquc,  parterre,  15; 
do.,  ceiling,  28;  stable,  7;  do.,  14;  hospital,  Madrid,  30;  do.,  do.. 
43;  air  of  bed-room  on  rising  in  the  morning,  48:  the  same  after 
being  ventilated  two  hours,  16;  railroad  car,  34;  workshop,  Munich, 
19;  full  room,  do.,  22;  lecture-room,  32;  beer-saloon,  40;  and  worst 
of  all  is  a  well-filled  school-room,  72  parts  of  carbonic  acid  in  10,000. 

That,  I  think,  is  enough.  Here  we  have  the  solution  of  the  whoio 
mystery. 

It  is  not  in  the  external  atmosphere  that  we  must  look  for  the  greatest 
impurities,  but  it  is  in  our  own  houses  that  the  blighting,  withering 
curse  of  foul  air  is  to  be  found.  We  are  thus  led  to  the  conclusion 
that  our  own  breath  is  our  greatest  enemy. 

The  "Health  of  Towns  Commission,"  in  their  investigations,  after 
examining  various  trades,  where  the  employees  were  conlmcd  mostly 
in  houses,  and  having  left  the  scavengers  to  the  last,  expecting  to  fii^d 
a  rich  harvest  of  mortality  among  them,  were  much  surprised  to  find 
them  more  healthy  than  many  very  clean  occupations,  but  which  were 
conducted  in  houses  instead  of  in  the  open  air.  I  have  not  the  sta- 
tistics before  me,  but  I  should  not  be  surprised  to  learn  that  that  sin- 
gular race  of  beings  that  live  in  the  sewers  of  Paris  were  as  healthy, 
if  not  even  more  so,  than  the  operatives  of  some  of  those  exquisitely 
beautiful,  clean,  air-tight  factories  of  New  England. 

There  was  quite  an  account  made  a  few  years  ago  of  the  wonderful 
cures  of  consumption  that  had  been  performed  by  the  patient  being 
removed  to  the  stable  where  he  could  be  in  close  proximity  to  the  cow, 
and  I  have  no  doubt  many  consumptive  patients  would  find  great 
benefit  by  such  a  course  of  treatment,  not  that  there  is  any  virtue  in 
the  smell  of  the  cow,  but  that  the  air  of  the  cow-stable  would  be  nearer 
pure  than  that  of  their  own  chamber. 

Many  go  or  send  their  families  to  the  country  in  summer  to  get  fresh 
air.  Some  go  to  the  sea-side,  others  to  the  mountains;  but  there  en« 


8 

sues  a  greater  change  in  a  few  minutes  in  a  close  bed-room  by  being 
occupied  by  a  family  than  there  is  difference  between  the  external  air 
of  any  city  and  that  of  the  country. 

The  reason  why  cities  are  so  much  more  unhealthy  than  the  country, 
is  not  because  the  air  in  the  street  is  so  much  more  impure,  but  be- 
cause the  houses  are  so  built  together  that  this  vast  ocean  of  air  can- 
riot  got  at  and  through  them  to  purify  them  as  it  does  in  the  houses  in 
the  country,  and  the  reason  why  Philadelphia  is  so  much  more  healthy 
than  its  neighbor,  New  York,  is  because  the  houses  here  are  built  more 
like  those  of  the  country,  so  that  the  air  can  sweep  all  around  them, 
and  sometimes  through  them. 

I  therefore  believe,  that  a  family  living  in  the  filthiest  street  in  our 
city,  if  they  were  careful  to  have  a  constant  current  of  air  from  that 
street,  filihy  as  it  was,  passing  through  the  house  at  all  times,  night 
and  day,  would  be  more  healthy,  other  things  being  equal,  than  a 
family  spending  their  winters  in  the  finest  house,  if  kept  air-tight,  in 
the  kcaitLiest  1-ication  in  the  city,  and  their  summer  in  the  country, 
especially  if  they  were  always  careful  to  exclude  the  night  air  from 
their  bed-rooms. 

I  say  "night  air;" — there  is,  unfortunately,  an  unnecessary  preju- 
dice against  what  is  termed  night  air,  which  means,  I  suppose,  fresh 
external  air  from  the  dark. 

To  show  that  this  is  not  a  new  idea,  I  will  read  a  few  lines  from  the 
writings  of  a  very  accurate  reasoner  and  an  eminently  practical  me- 
chanic and  philosopher,  one  whom  I  consider  even  now  one  of  the  very 
best  authorities  upon  the  subject  of  heating  and  ventilation.  I  mean 
the  illustrious  man  after  whom  this  Institute  was  named,  Benjamin 
Franklin. 

In  his  letter  to  Dr.  Ingenhaus,  physician  to  the  Emperor,  at  Vienna, 
he  says:  *  *  *  *  "for  some  are  as  much  afraid  of  fresh  air  as 
persons  in  the  hydrophobia  are  of  fresh  water.  I  myself  had  formerly 
this  prejudice — this  aerophobia,  as  I  now  account  it, — and  dreading  the 
supposed  dangerous  effects  of  cool  air,  I  considered  it  an  enemy,  and 
closed  with  extreme  care  every  crevice  in  the  rooms  I  inhabited.  Ex- 
perience has  convinced  me  of  my  error.  I  now  look  upon  fresh  air  as 
a  friend :  I  even  sleep  with  an  open  window.  I  am  persuaded  that  no 
common  air  from  without  is  so  unwholesome  as  the  air  within  a  close 
room  that  has  been  often  breathed  and  not  changed.  Moist  air,  too, 
which  I  formerly  thought  pernicious,  gives  me  now  no  apprehensions  ; 
for  considering  that  no  dampness  of  air  applied  to  the  outside  of  my 


skin  can  be  equal  to  what  is  applied  to  and  touches  it  within,  my 
whole  body  being  full  of  moisture,  and  finding  I  can  lie  two  hours  in 
a  bath  twice  a  week,  covered  with  water,  which  certainly  is  much 
damper  than  any  air  can  be,  and  this  for  years  together,  without 
catching  cold,  or  being  in  any  other  manner  disordered  by  it,  I  no 
longer  dread  mere  moisture,  either  in  air,  or  in  sheets  or  shirts;  and 
I  find  it  of  importance  to  the  happiness  of  life,  the  being  freed  from 
vain  terrors,  especially  of  objects  that  we  are  every  day  exposed  in- 
evitably to  meet  with. 

"You  physicians  have  of  late  happily  discovered,  after  a  contrary 
opinion  had  prevailed  some  ages,  that  fresh  and  cool  air  does  good  to 
persons  in  the  small-pox  and  other  fevers.  It  is  to  be  hoped,  that  in 
another  century  or  two  we  may  all  find  out  that  it  is  not  bad  even  for 
people  in  health.  And  as  to  moist  air,  here  I  am  at  this  present  writ- 
ing in  a  ship  with  above  forty  persons,  who  have  had  no  other  but  moist 
air  to  breathe  for  six  weeks  past ;  everything  we  touch  is  damp,  and 
nothing  dries,  yet  we  are  all  as  healthy  as  we  should  be  on  the  mountains 
of  Switzerland,  whose  inhabitants  are  not  more  so  than  thosa  of  Ber- 
muda or  St.  Helena,  islands  on  whose  rocks  the  waves  are  dashed  into 
millions  of  particles,  which  fill  the  air  with  damp,  but  produce  no  dis- 
eases, the  moisture  being  pure,  unmixed  with  the  poisonous  vapors  aris- 
ing from  putrid  marshes  and  stagnant  pools,  in  which  many  insects  die 
and  corrupt  the  water.  These  places  only,  in  my  opinion,  (which,  how- 
ever, I  submit  to  yours,)  afford  unwholesome  air;  and  that  it  is  not 
the  mere  water  contained  in  damp  air,  but  the  volatile  particles  of 
corrupted  animal  matter  mixed  with  that  water,  which  renders  such 
air  pernicious  to  those  who  breathe  it;  and  I  imagine  it  a  cause  of  the 
same  kind  that  renders  the  air  in  close  rooms,  where  the  perspirable 
matter  is  breathed  over  and  over  again  by  a  number  of  assembled 
people,  so  hurtful  to  health. 

"  After  being  in  such  a  situation  many  people  find  themselves  affected 
by  that  febricula,  which  the  English  alone  call  a  cold,  and,  perhaps, 
from  that  name,  imagine  they  have  caught  the  malady  by  going  out 
of  the  room,  when  it  was,  in  fact,  by  being  in  it." 

Now,  to  show  that  his  hopes  have  not  yet  been  fully  realized,  although 
one  century  has  nearly  closed  since  he  wrote  what  I  have  just  read, 
and  this  unnecessary  and  unfortunate  prejudice  against  night  air  still 
prevails  extensively,  I  will  read  a  few  lines  from  the  highest  public 
medical  authority  in  this  city.  It  is  the  instructions  of  the  Board  of 
Health  for  the  prevention  of  cholera  for  1866: 


10 


ARTICLE — "VENTILATION." 

"Your  premises,  particularly  sleeping  apartments  and  cellars,  should 
be  thoroughly  ventilated.  Ventilation  is  no  less  a  purifier  than  water. 

"It  cleanses  by  oxidizing  and  drying.  Keep  your  houses  open  and 
your  windows  hoisted  during  the  day  in  good  weather,  and  from  ten 
o'clock  until  four  in  the  afternoon,  that  they  may  have  the  full  benefit 
of  sunlight  and  free  circulation  of  pure  air.  During  the  remaining 
hours  of  the  day,  and  through  the  night,  keep  the  windows  dosed. 
When  the  weather  is  cool  or  rainy,  be  sure  to  keep  a  fire  in  the  house, 
in  order  to  prevent  dampness,  or  in  sparsely  settled  neighborhoods,  or 
in  the  suburbs  of  the  city,  have  a  fire  in  the  house  the  entire  season." 

On  page  9  we  read:  "Be  careful  to  dress  comfortably  for  the  season, 
avoid  the  night  air  as  much  as  possible,  and  when  thus  exposed,  put 
on  an  extra  garment  and  do  not  go  into  the  night  air  when  in  a  state 
of  perspiration." 

Thus,  while  recognizing  the  great  value  and  importance  of  ven- 
tilation in  a  general  way,  they  give  the  most  definite  instructions  for 
thoroughly  and  most  effectually  preventing  it,  because  it  is  at  night, 
especially  when  we  are  asleep  and  cannot  move  from  the  air,  that  the 
air  ought  to  be  moved  from  us. 

The  frequent  recommendations  to  avoid  "night  air"  are  simply 
recommendations  to  smother  ourselves  to  death,  because  the  foul,  poison- 
ous exhalations  from  our  lungs  cannot  be  removed  from  our  chambers 
without  being  replaced  by  night  air ;  there  is  no  other  fresh  air  at  night 
but  night  air. 

The  recommendation,  to  build  a  fire  in  the  house  on  cool  days,  and  in 
low  marshy  districts  every  day  in  the  year,  is  an  excellent  one. 

The  recommendations  to  dress  warmly  and  to  avoid  checking  a  per- 
spiration suddenly,  are  valuable  suggestions  and  too  much  attention 
cannot  be  paid  to  them. 

But  they  are  of  equally  great  importance  in  reference  to  day  air  as 
to  night  air. 

To  shelter  oneself  from  the  sudden  change  of  temperature  after  sun- 
down is  an  animal  instinct,  and  a  very  necessary  one,  which  is  strongly 
implanted  in  man  and  beast  alike. 

The  harm  comes  from  the  fact  of  so  intelligent  and  intellectual  a 
oody  as  the  Board  of  Health  of  Philadelphia  encouraging  the  ac- 
complishment of  this  very  desirable  object,  by  thwarting  that  great 
universal  law  of  our  Creator, -the  ceaseless  agitation  of  the  air  by  which 


11 


it  purifies  itself,  (and  by  which  perversion  of  nature's  laws  millions  ar6 
already  being  killed  unnecessarily  every  year,)  instead  of  their  en- 
couraging its  accomplishment  in  that  much  more  healthy  and  rational 
way  by  adding  more  clothing  or  more  fuel  to  the  fire,  and  still  con- 
tinuing to  breathe  the  pure  air  at  night  as  well  as  in  the  day-time. 

I  have  practised  for  many  years  sleeping  with  my  windows  open 
every  night,  summer  and  winter,  allowing  the  unobstructed  breeze  to 
flow  across  my  bed,  to  the  great  improvement  of  my  health  and  strength. 

There  is  no  objection  in  a  well  ventilated  room  to  having  a  fire  if 
desired.  A  small  room  with  a  hot  stove  or  open  fire  and  the  windows 
open,  is  much  more  wholesome  than  a  large  air -tight  room  freezing  cold. 

LET  us  illustrate  this  by  a  simple  experiment.  Here  we  have  a  very 
small  tube,  in  which  we  place  a  lighted  candle,  occupying  nearly  the 


Fig.  1. 


I  '  U 


entire  space — this  burns  brightly, 
you  see. 

Here  we  have  another  glass 
chamber,  much  handsomer  and 
twenty  times  as  large;  we  also 
place  a  similar  candle  in  it,  that 
burns  with  equal  brightness,  but 
watch  them  both  for  a  few  mo- 
ments— see  how  rapidly  this  light 
in  the  large  chamber  diminishes 
in  size. 

That  represents,  in  a  beautiful  manner,  the 
diminished  force  of  your  life  in  an  air-tight  room.  There  it  goes — 
entirely  extinguished  by  foul  air  in  so  short  a  time,  but  the  other 
continues  to  burn  just  as  brightly  as  when  first  lighted.  The  smaller 
one  had  the  window  open,  so  to  speak ;  we  will  imagine  the  candle  in 
the  large  chamber  to  be  a  consumptive  patient  who  thought  the  room 
so  large  he  did  not  need  the  windows  open.  Remember,  therefore, 
that  no  matter  how  small  your  room  is,  if  there  is  a  constant  circula- 
tion of  fresh  air  through  it,  the  lamp  of  youc  life  will  burn  brightly ; 
but  if  ever  so  large  and  air-tight,  your  life  will  soon  be  extinguished. 
Instead  of  averting  the  cholera  by  avoiding  fresh  air  at  night,  the 
experience  of  the  last  summer  seems  to  have  taught  us  just  the  con- 
trary; for  whilst  most  physicians  admit  that  they  are  still  unable  to 
explain  satisfactorily,  the  cause  or  remedy  for  this  most  mysterious 
disease,  that  has  within  a  lifetime  carried  its  fifty  millions  of  victims 
from  time  to  eternity,  they  almost  universally  believe  it  is  a  foul  air 
poison,  and  they  have  as  yet  found  no  surer  prevention  than  pure  air. 


12 

One  of  the  most  striking  illustrations  of  this,  and  perhaps  one  of 
the  most  wonderful  cures  of  cholera  on  record,  was  that  of  the  New 
York  Workhouse  on  Blackwell's  Island.  It  lasted  only  nine  days, 
but  in  that  brief  period  one  hundred  and  twenty-three  out  of  eight 
hundred  inmates  died.  I  visited  the  building  with  Dr.  Hamilton,  on 
the  third  day  after  its  appearance,  but  the  hospital  then  contained 
sixty  or  seventy  patients,  and  some  twenty-five  or  thirty  had  died 
within  twenty-four  hours. 

Dr.  Hamilton  attributed  the  rapid  propagation  and  fatality  of  the 
disease,  after  it  once  had  gained  admission,  mainly  to  confinement 
and  crowding.  It  was  observed  that  the  cholera  was  confined,  for 
several  days,  among  the  women ;  the  women  had  the  smallest  apart- 
ments, were  most  crowded  in  their  cells,  and  with  few  exceptions, 
were  employed  within  the  building,  in  close  contact  with  each  other 
during  the  day.  The  men  were  employed  mostly  in  the  quarries  and 
out  of  doors. 

The  doctor's  prescription  on  that  occasion  is  worth  studying.  It 
is  very  short  and  simple,  however. 

A  slight  change  was  made  in  the  diet ;  disinfectants  were  used  ; 
fifteen  drops  of  the  tincture  of  capsicum  with  an  ounce  of  whisky,  as 
a  stimulant  at  night,  was  all  the  medicine  given  to  each  individual. 
But  the  great  means  the  doctor  relied  upon  for  success,  was  pure  air 
all  the  time.  They  were  kept  out  of  doors  from  morning  until  night, 
and  all  the  windows  were  kept  open  night  and  day ;  and  although  in 
the  hot  weather  of  summer,  fire  was  made  in  the  wards,  to  insure 
more  perfect  ventilation.  In  six  days  after  the  initiation  of  these 
simple  hygienic  measures,  the  epidemic  entirely  disappeared. 

The  disorders  and  sickness  caused  by  the  too  rapid  chilling  of  the 
unprotected  body  after  sundown,  have  given  rise,  I  have  no  doubt,  to 
that  erroneous  popular  prejudice  so  common  among  all  classes,  even 
those  of  education  and  ordinarily  good  common  sense,  who  imagine 
there  is  some  peculiar  poison  or  source  of  unhealthiness  in  the  air  at 
night,  that  is  not  contained  in  the  air  in  the  day-time.  It  will  no 
doubt  greatly  relieve  the  minds  of  these  from  such  "vain  terrors," 
and  prove  most  conclusively  the  entire  fallacy  of  such  reasoning,  to 
examine  these  tables  again.  In  the  copies  I  have  made,  I  have  not 
classified  the  results  given  by  day  and  by  night,  but  a  careful  exami- 
nation in  detail,  fails  to  show  any  appreciable  difference  in  the  aggre- 
gate, by  day  or  by  night. 

Mene's  numerous  experiments  on  the  air  in  Paris,  gave  less  carbonic 
acid  at  night  than  in  the  day-time. 


13 


Lewey's  analysis  on  the  Atlantic  ocean,  one  thousand  miles  from 
the  coast,  gave  a  decided  excess  in  the  day  over  that  of  the  night. 
He  attributes  this  to  the  action  of  the  sunlight  upon  the  ocean 
liberating  the  gases  which  it  holds  in  solution. 

In  cities  there  is  a  much  larger  quantity  given  off  from  burning 
coals  of  factories  in  the  day-time  than  at  night. 

It  is  not  improbable,  however,  that  the  more  rapid  evaporation  of 
moisture  towards  evening  may  carry  with  it  the  volatile  particles  of 
corrupted  animal  and  vegetable  matter  to  an  extent  slightly  in  excess 
of  that  which  occurs  in  the  morning,  but  it  is  believed'these  would 
not  equal  the  greater  contamination  from  burning  coals,  and  the 
usually  greater  stillness  of  the  air,  producing  partial  stagnation,  so 
that  the  air  would  be  a  little  nearer  pure  at  night  than  in  the  day-time. 
And  how  unmistakably  do  all  these  investigations  prove  what  we 
ought  to  have  known  and  accepted  without  a  moment's  hesitation,  that 
the  Creator,  who  has  made  such  vast  and  such  minute  provisions  for 
supplying  every  living  creature  with  a  constant  and  copious  supply  of 
fresh  air,  and  has  made  it  so  important  for  their  existence  that  they  can- 
not live  a  moment  without  it,  has  made  the  air  at  night  just  as  pure 
and  wholesome  as  in  the  day-time. 

We  have  thus  traced  the  scourge  of  foul  air  to  our  houses,  and  much 
of  it  to  our  bed-rooms.  The  next  question  is,  how  to  get  clear  of  it. 

We  want  to  know,  however,  what  poisons  the  air,  so  as  to  know  in 
what  part  of  the  room  it  is  to  be  found. 

We  will  try  a  very  simple  experiment,  to  show  you  what  a  deadly 
poison  the  breath  is, — to  the  flame  of  a  candle,  at  any  rate. 

Here  is  a  simple  glass  tube,  open  at  both  ends — an  ordinary  lamp 
chimney — a  candle  burns  freely  as  you  see,  and  would  burn  so  all 
night,  if  it  did  not  burn  out.  '  I  will  now  remove 
the  candle,  and  breathe  into  the  tube  through  this 
pipe,  and  now  you  see  how  suddenly  the  candle  is 
extinguished  as  I  drop  it  in  again. 

Animals  are  killed  suddenly  or  after  a  more 
prolonged  struggle,  by  the  exhaled  breath,  accord- 
ing to  the  activity  or  sluggishness  with  which  the 
blood  circulates — a  bird  would  be  killed  very 
soon — some  partially  torpid  animals  would  live  a 
long  time.  Man  has  great  endurance — struggles 
long  and  hard ;  but  if  closely  confined,  will  be 
poisoned  to  death  in  one  night,  as  in  the  case  of 
those  confined  in  the  celebrated  Black  Hole  of  Calcutta,  and  on  board  of 


14 

vessels  where  they  have  been  confined  below  decks  in  time  of  a  storm. 
Others  will  struggle  on  longer,  as  in  the  case  of  the  two  thousand  and 
twenty-six  who  died  of  consumption  last  year,  in  Philadelphia. 

And  now  let  us  see  in  which  part  of  the  room  this  deadly  poison 
of  our  breath  is  mostly  found. 

It  is  the  popular  idea,  that  because  the  body,  and  consequently  the 
breath,  is  warmer  than  the  ordinary  temperature  of  a  room,  it  rises 
and  accumulates  at  the  ceiling. 

Upon  this  theory  most  of  our  buildings  have  been  ventilated  whenever 
any  attention  whatever  has  been  given  to  the  subject;  but  that  theory 
is  incorrect ;  consequently,  all  practice  based  thereon  is  also  wrong. 

This  subject  of  the  direction  taken  by  the  breath  upon  leaving  the 
body,  has  been  warmly  discussed  within  a  few  years.  It  has  been  a 
very  difficult  matter  to  prove  conclusively  and  satisfactorily,  but  I 
think  we  have  devised  some  very  simple  experiments  that  will  prove 
to  you  very  clearly  what  we  have  stated. 

I  have  here  a  simple  glass  tube  two  feet  long  and  one  and  a  half 
inch  interior  diameter ;  one  end  is  closed  with  a  rubber  diaphragm, 

through  which  is  passed  a  small 
rubber  tube — the  other  end  is 
all  open.  We  will  rest  this  about 
horizontal,  and  taking  a  little 
smoke  in  the  mouth,  it  will  be 
discharged  with  the  breath  into  the  glass  tube;  it  is  first  thrown 
towards  the  top,  but  it  soon  falls,  and  now  see  it  flowing  along  the 
bottom  of  the  tube  like  water — watch  it  as  it  reaches  the  far  end — 
there,  see  it  fall  almost  like  water. 

Now,  by  raising  the  closed  end  of  the  pipe,  you  see  we  can  pour  it 
all  out,  and  by  filling  it  again  and  raising  the  other  end,  it  falls  back. 

Thus  you  see  that,  notwithstanding  the  extra  warmth  in  the  breath, 
it  is  heavier  than  the  atmosphere,  and  falls  to  the  floor  of  an  ordi- 
nary room  like  this,  say,  when  the  temperature  is  from  60°  to  70°. 
This  is  owing  to  the  carbonic  acid  and  moisture  contained  in  it. 

I  have  varied  this  experiment  in  a  number  of  ways,  by  passing  it 
through  smaller  tubes  and  discharging  it  into  the  air  in  one  or  two 
seconds  after  leaving  the  lungs,  and  by  passing  it  through  water  of 
various  temperatures,  and  discharging  it  into  rooms  of  different 
temperatures,  with  the  same  general  results.  As  the  tempera 
ture  of  the  air  diminishes,  the  tendency  of  the  discharged  breath  to 
rise  increases.  Much  care  is  required  in  conducting  these  experiments, 


15 


to  avoid  as  much  as  possible,  the  local  currents  which  are  always 
present  in  a  room. 

This  is  a  very  important  fact  to  be  borne  in  mind ;  yet  notwith- 
standing this,  there  are  times,  under  certain  circumstances,  in  which 
the  foul  air  will  be  found  in  excess 
at  the  top  of  the  room. 

For  the  further  examination  of 
this  subject,  we  have  here  a  little 
glass-house  with  glass  chimneys 
and  fire-place  in  the  first  and 
second  stories. 

As   the   flame  of  a  candle  is 

such  a  beautiful  emblem  of  human   ___^ 

life,  we  will  remove  the  roof  and 

part  of  the  floor  of  the  second  story,  and  place  four  candles  in  our 
house.  They  are  all  of  different  heights,  you  see.  We  will  call 
them  a  father,  mother  and  two  children. 

As  carbonic  acid  is  that  much  dreaded  poison  in  our  breath,  and 
the  heavy  portion  of  it  which  causes  it  to  fall  to  the  floor,  we  will 
make  a  little  by  placing  a  few  scraps  of  common  marble  in  this  glass 
vessel,  and  pouring  over  it  some  sulphuric  acid. 

It  is  now  forming,  and  will  fall  and  flow  across  the  floor  the  same 
as  carbonic  acid  does  when  it  pours  into  a  basement  from  the  gutters 
on  the  street  or  filthy  yards  where  it  is  formed,  and  before  it  is 
absorbed  or  diluted  by  the  current  of  pure  air  sweeping  over  them. 
It  first  kills  the  smallest  child,  because  it  is  nearest  the  floor.  You 
remember  the  excessive  infantile  mortality  in  this  city  in  1865.  This 
is  partially  owing  to  their  breathing  more  of  this  foul  air  near  the 
floor,  and  partially  owing  to  the  great  fear  of  their  mothers  and 
nurses,  of  letting  the  little  innocents  get  a  breath  of  fresh  air  for  fear 
it  will  give  them  colic,  and  consequently  they  smother  them  to  death. 

The  other  child  dies  next,  and  then  the  mother,  and  lastly  the 
father. 

Thousands  are  thus  poisoned  to  death  by  their  own  breath  every  year. 
But  did  you  ever  see  a  physician's  certificate  that  gave  you  any 
such  idea?  Why  do  not  the  doctors  tell  the  living,  in  such  language 
as  they  can  understand,  what  killed  their  friends,  so  they  may  avoid 
it  in  th^ir  own  case,  instead  of  giving  it  in  some  Latin  terms  which  I 
fear  many  interpret  to  mean  some  special  dispensation  of  Divine 


16 

Providence  instead  of  the  true  cause — their  utter  disregard  of  the 
laws  their  Creator  made  for  the  preservation  of  their  health  ? 

Had  this  family  known  enough  about  ventilation  to  have  kept  the 
fire-place  open,  with  a  little  fire  in  it  now  and  then,  they  would  not 
have  been  thus  killed. 

Let  us  see — we  will  take  out  the  fire-board  which  has  been  put  in 
to  make  the  room  look  a  little  neater,  and  with  a  very  small  light 
there  to  create  a  draft  in  the  chimney. 

We  will  again  light  the  candles,  and  pour  in  the  poisonous  breath. 
Ah  !  there  goes  the  little  one — he  is  hardly  high  enough  to  keep  out 
of  that  deadly  current  flowing  across  the  floor. 

We  shall  have  to  let  it  in  a  little  slower,  or  we  will  set  him  on  a 
platform,  as  many  persons  who  have  carefully  studied  this  subject, 
consider  it  judicious  to  do.  Now,  by  the  smoke  from  this  taper,  you 
can  see  the  air  is  flowing  across  the  floor  and  up  the  chimney. 

There  has  been  a  steady  current  flowing  in  long  enough  to  havt, 
filled  the  house,  but  the  lights  are  all  burning  brightly,  and  you  thus 
see  the  value  of  an  open  fire-place  for  ventilation.  Thousands 
of  lives  are  thus  saved,  and  many  more  would  be  if  all  fire-places 
were  kept  open.  I  have  recommended  hundreds  of  fire-boards  to  be 
cut  up  for  kindling-wood,  as  I  consider  this  is  the  best  use  that  can 
be  made  of  all  fire-boards. 

Never  stop  up  a  fire-place  in  winter  or  summer,  where  any  living 
being  stays  night  or  day.  It  would  be  about  as  absurd  to  take  a 
piece  of  elegantly  tinted  court-plaster  and  stop  up  the  nose,  trusting  to 
the  accidental  opening  and  shutting  of  the  mouth  for  fresh  air,  because 
you  thought  it  spoiled  the  looks  of  your  face  so  to  have  two  such  great 
ugly-looking  holes  in  it,  as  it  is  to  stop  your  fire-place  with  elegantly 
tinted  paper  because  you  think  it  looks  better. 

If  you  are  so  fortunate  as  to  have  a  fire-place  in  your  room,  paint 
it  when  not  in  use ;  put  a  bouquet  of  fresh  flowers  in  every  morning, 
if  you  please,  or  do  anything  to  make  it  attractive;  but  never  close  it. 

Now,  there  are  other  conditions  in  which  a  fire-place  or  an  opening 
near  the  floor,  will  not  answer  for  ventilation.  This  occurs  in  rooms 
where  the  air  is  made  impure  by  burning  lamps  or  gas,  and  where  the 
fresh  air  entering  the  room  is  cooler  than  the  temperature  of  the 
room  itself. 

To  illustrate  this,  we  will  put  the  roof  on  and  take  the  entire  floor 
away,  or  as  it  will  be  a  little  more  convenient,  we  will  represent 
it  by  this  glass-house,  using  this  shade  for  that  purpose. 


IT 

This  is  supported  some  six  inches  from  the  floor,  and  has  no 
bottom.  By  lighting  another  candle  and  standing  it  outside,  you 
can  judge  by  comparison,  of  the  foulness  of  the 
air  inside. 

The  tallest  one  is  effected  first,  this  time. 
You  see  that  is  a  perfectly  formed  light,  but  it 
gives  but  about  half  the  light  the  one  does  on  the 
outside ;  this  is  the  way  with  many  of  us  who  are 
obliged  to,  or  rather  do,  breathe  foul  air  half  the 
time. 

We  often  think,  by  comparing  ourselves  with 
others  around  us,  that  we  are  pretty  fair  specimens  of  humanity, 
while  really  we  do  not  give  more  than  half  the  light  in  the  world 
that  we  ought  to  do,  and  kill  ourselves  before  our  work  is  half  done. 

You  see  the  two  tallest  are  dead  already,  and  the  others  will  soon 
follow — there  they  go.  Here  is  the  bottom  of  the  house  removed, 
and  yet  these  candles  all  went  out  for  want  of  fresh  air. 

Therefore,  when  we  see  the  air  is  made  impure  by  burning  candles 
or  gas  lights,  owing  to  its  exceeding  heat,  the  foul  air  is  mostly  at 
the  top  of  the  room,  and  especially  when  the  fresh  air  enters  cooler 
than  the  air  in  the  room.  We  will  find,  however,  that  in  a  very  few 
minutes  the  candles  will  relight  long  before  the  contained  air  or  the 
glass  shade  cools  down  to  the  temperature  of  the  room. 

The  products  of  combustion,  like  those  of  respiration,  are  heavier 
than  the  ordinary  atmosphere,  and  consequently  fall  to  the  floor  very 
soon  if  not  removed  while  very  hot,  by  special  openings  immediately 
over  them  in  the  ceiling ;  after  it  has  thus  fallen,  provision  must  be 
made  for  its  removal  from  the  level  of  the  floor,  in  connection  with 
the  foul  air  from  the  breath.' 

I  hope  that  by  these  few  simple  experiments,  and  the  statistics  pre- 
sented here  this  evening,  we  have  strengthened  your  previous  convictions 
of  the  importance  of  fresh  air,  because  we  are  well  aware  that  you  wil) 
find,  as  you  proceed  in  your  investigations  of  this  subject,  that  it  ia 
frequently  surrounded  with  complications;  yet  the  laws  governing  the 
circulation  of  air  of  different  temperatures,  are  as  fixed  and  immovable 
as  the  laws  governing  the  rising  and  setting  of  the  sun,  and  with  a 
very  little  careful  investigation,  can  be  easily  understood. 

And  we  believe  no  similar  amount  of   money  or  thought,   will 
produce  a  greater  amount  of  satisfaction  than  the  increased  health, 
strength  and  happiness  thus  secured. 
B 


18 


LECTURE  II. 

As  I  stated  in  our  last  lecture,  much  interest  is  being  awakened, 
in  this  country  and  in  Europe,  by  recent  investigations  showing  the 
enormous  numbers  of  untimely  deaths  that  are  caused  throughout  all 
classes  of  society  by  foul  air. 

It  would  have  been  a  startling  announcement,  ten  years  ago,  to 
have  stated  that  impure  air  caused  as  many  deaths,  and  as  much 
sickness,  as  all  other  causes  combined,  and  yet  the  most  diligent  and 
accurate  investigations  are  rapidly  approaching  that  conclusion. 

Few  really  comprehend  the  immense  pecuniary  loss,  to  say  nothing 
of  the  amount  of  suffering,  that  we  endure  by  this  extra  and  easily 
preventible  amount  of  sickness. 

I  propose,  this  evening,  to  enter  upon  the  consideration  of  one  of 
the  most  important  parts  of  our  subject — the  effect  produced  by  HEAT 
upon  the  movements  of  air. 

I  think  it  probable  that  many  of  us  do  not  comprehend  the  actual 
reality  of  the  air. 

We  are  apt  to  say  of  a  room  that  has  no  carpet  and  furniture  in  it, 
that  it  has  nothing  in  it,  while,  if  it  is  full  of  air,  it  has  a  great  deal 
in  it. 

A  room  between  twenty-seven  and  twenty-eight  feet  square  con- 
tains one  ton  of  air — a  real  ton,  just  as  heavy  as  a  ton  of  coal.  Now, 
there  is  not  only  twenty-seven  feet,  but  more  than  twenty-seven 
miles  of  air  piled  on  top  of  us.  The  pressure  of  the  atmosphere  at 
the  level  of  the  ocean  is  about  fifteen  pounds  to  the  square  inch.  An 
ordinary  sized  man  sustains  a  pressure  of  about  fifteen  tons,  and 
were  it  not  that  this  pressure  is  equal  in  all  directions,  we  would  be 
crushed  thereby. 

We  must  accustom  our  minds,  therefore,  to  consider  air  a  real  sub- 
stance, and  that  it  is  as  totally  unable  to  move  itself,    or  to  be 
moved,  without  power,  as  water  or  coal.     It  requires  just  as  much 
power  to  move  a  ton  of  air  from  the  cellar  to  the  second  story,  as 
it  does  a  ton  of  coal. 

Heat  is  the  great  moving  power  of  air.  Those  whose  attention 
has  not  been  especially  directed  to  the  subject  of  the  amount  of  power 
exerted  by  the  sun's  rays  upon  the  earth,  have  little  conception  of 
its  magnitude. 

The  power  of  all  the  horses  in  the  world,  added  to  the  power  of  all 
the  locomotives,  and  of  all  the  immense  steam  engines  in  all  the 


19 

world,  express  but  a  small  fraction  of  the  power  exerted  by  the  sun'a 
rays  upon  the  earth.  It  is  estimated  to  be  sufficient  to  boil  five  cubic 
miles  of  ice-cold  water  every  minute. 

His  rays  are  the  chosen  power  of  the  Creator  for  moving  all  matter 
upon  the  globe.  It  is  his  rays  that  lie  buried  in  the  vast  coal  fields 
beneath  the  earth.  His  rays  cause  every  spear  of  grass  to  grow, 
rear  the  mighty  oak,  form  the  rose,  burst  its  beautiful  buds,  and 
send  its  perfume  through  the  air. 

No  bird  warbles  its  sweet  music  in  the  air,  no  insect  breathes,  save 
by  bis  power,  and  all  animals  love  to  bask  in  the  genial  glow  of  his 
light  and  heat.  He  rolls  the  scorching  air  of  the  tropics  to  frozen 
lands,  and  wafts  the  ships  across  the  seas.  He  forces  the  heated  waters 
of  the  equator  to  the  poles,  tempering  all  the  earth.  He  lifts  the 
water  from  the  sea  to  sprinkle  all  the  land  and  cap  the  distant  moun- 
tains with  eternal  snow. 

Now,  let  us  examine  a  little  more  minutely  how  this  influence  is 
exerted  upon  the  air,  which  is  the  subject  we  are  especially  interested 
in  at  present. 

Does  it  commence  at  the  top,  and  heat  it,  layer  by  layer,  until  it 
reaches  the  bottom?  Not  at  all;  but  it  passes  through  the  whole 
forty-five  miles  of  air,  heating  it  very  little,  if  any,  and  falls  upon  the 
solid  substances  at  the  earth's  surface,  heating  them,  which,  in  turn, 
heat  the  air  by  its  individual  particles  coming  into  immediate  contact 
with  those  solid  hotter  substances. 

We  will  endeavor  to  illustrate  this  in  a  crude  way. 

Fig.  7. 


Here  we  have  a  tin  tube,  a,  fifteen  feet  long  and  ten  inches  in  di- 
ameter, open  at  both  ends ;  two  feet  from  one  end  we  introduce  this 


20 

ascending  pipe,  6,  the  upper  end  of  which  is  merely  inserted  in  a 
small  flue,  extending  to  the  top  of  the  building.  The  height  of  this 
flue  is  sufficient  to  make  a  current  of  air  pass  through  this  tube,  as 
you  will  see  by  holding  this  smoking  taper  at  the  far  end.  We  will 
no-v  place  a  large  heated  ball,  o,  at  this  end,  and  outside  of  that  we 
will  place  this  reflector,  d,  pressing  it  quite  close  to  the  end  of  the 
tube,  so  that  no  air  can  enter  here. 

The  rays  of  heat  from  this  ball,  or  from  any  other  warm  body,  are 
thrown  like  rays  of  light,  in  every  direction  equally  ;  there  would, 
therefore,  be  some  of  the  rays  thrown  through  this  tube  to  the  other 
end  without  any  reflector,  but  the  proportion  that  would  reach  the 
other  end  would,  of  course,  be  small. 

We  therefore  collect  those  going  the  other  way,  and  change  their 
course,  and  then  send  them  straight  through  the  tube  to  the  far  end. 
We  will  place  another  reflector,  e,  at  the  far  end,  to  receive  and 
concentrate  those  rays,  in  the  focus  of  which  we  will  place  a  candle, 
F,  with  a  little  phosphorus  on  it,  to  show  you  that  the  rays  of  heat 
are  passing  through. 

There  you  see  the  candle  is  lighted,  thus  proving  that  there  is  a 
strong  current  of  radiant  heat  coming  from  the  hot  ball,  through 
the  tube  to  this  end.  And  you  see  by  this  smoke  that  there  is  a  cur- 
rent of  air  passing  the  other  way. 

Now,  we  want  to  know  how  much  that  air  is  heated  in  passing  the 
whole  length  of  this  tube  against  that  shower  of  radiant  heat,  or 
whether  air  absorbs  radiant  heat  at  all ;  but,  before  going  to  the  other 
end,  where  the  hot  ball  is,  we  will  take  two  thermometers  that  have 
been  lying  here,  side  by  side,  both  indicating  a  temperature  of  69°. 
One  of  them,  g,  we  will  hang  at  this  end,  about  opposite  to  the  centre 
of  our  tube,  which,  I  think,  will  give  us  a  fair  average  of  the  entering 
air,  first  removing,  however,  the  candle  that  has  been  lighted,  and 
the  reflector. 

We  will  hang  the  other  thermometer  in  the  ascending  tube,  at  the 
end  near  the  heated  ball.  We  have  had  two  glasses,  H,  inserted 
here,  so  that  we  mi^ht  observe  what  was  going  on  within  by  the  smoke 
from  this  taper.  You  see  there  is  a  strong  current  of  air  passing  up 
the  tube,  all  of  which  must  come  from  the  far  end,  flowing  against 
the  strong  current  of  radiant  heat  going  in  the  opposite  direction. 
Now,  leaving  this  thermometer  to  rise  or  fall  according  to  the  tem- 
perature of  the  air  flowing  through,  we  will  go  to  the  other  end  and 
examine  another  very  interesting  part  of  this  experiment :  it  is  the 


21 

manner  in  which  the  radiant  heat  is  received  and  appropriated  by 
different  substances. 

Radiant  heat  is  thrown  from  a  hot  body  in  every  direction  equally, 
but  no  two  kinds  of  substances  receive  those  rays  of  heat  in  the  same 
manner,  nor  do  they  make  the  same  use  of  them  after  they  have  re- 
ceived them. 

Every  substance  receiving  heat,  however,  must  give  a  strict  ac- 
count of  it.  It  must  give  out  an  equal  amount  of  heat,  or,  what  is 
taken  as  an  equivalent,  some  action  or  power. 

I  have  a  sheet  of  ordinary  tin,  and  as  I  hold  this  polished  side  be- 
hind this  light,  you  see  it  throws  a  belt  of  light  across  the  room;  and 
as  I  put  it  in  front  of  the  end  of  our  tube,  and  turn  it  so  that  the 
rays  of  heat  will  be  reflected  in  your  faces,  I  think  some  of  you  will 
be  able  to  feel  the  reflected  heat.  The  rays  of  heat  are  turned  from 
their  course,  and  thrown  'in  a  belt  across  the  room,  similar  to  the  rays 
of  light. 

But  you  cannot  give  away  and  keep  the  same,  thing.  This  bright 
polished  surface  appropriates  but  a  very  small  portion  of  the  radiant 
heat.  A  thermometer  hanging  for  some  minutes  against  the  back 
has  scarcely  risen  one  degree ;  but  we  have  given  the  other  side  a 
coating  of  lamp  black,  with  a  little  varnish,  and  by  turning  that  side 
towards  the  pipe,  the  result  will  be  quite  different.  By  this  coat  of 
clack  varnish  the  whole  character  of  the  sheet  of  tin  is  changed. 
The  black,  however,  has  but  little  to  do  with  it;  if  itwere white,  or 
red,  or  blue,  the  formation  of  the  surface  being  similar  in  every  re- 
spect, the  result  would  be  the  same  almost  precisely. 

Instead  of  acting  merely  as  a  guide-post,  to  change  the  direction 
only  of  the  rays  of  heat,  as  before,  it  now  becomes  a  receiving  depot, 
absorbing  nearly  all  the  heat  that  comes  to  it.  It  must  soon  become 
filled,  however.  The  thermometer  hanging  at  the  back  has  risen  six 
degrees  already,  and  is  going  up  rapidly ;  it  must  soon  begin  to  dis- 
tribute its  extra  stores.  But  mark  the  different  manner  of  distri- 
buting the  heat.  Instead  of  reflecting  the  whole  all  in  one  direction, 
as  when  received  on  the  other  side,  it  now  radiates  them  equally  in 
every  direction. 

Some  solid  substances  allow  the  rays,  both  of  heat  and  light,  to 
pass  directly  through  them  without  either  reflecting  or  absorbing 
them.  Other  substances  allow  the  rays  of  light  to  pass  through  them, 
but  absorb  much  of  the  radiant  heat,  like  clear  glass. 

Rock  salt  is  one  of  the  best  non-absorbents  of  radiant  heat,  allow- 
ing nearly  the  whole  of  the  rays  of  heat  to  pass  through  unobstructed. 


22 

We  will  now  return  to  our  experiment  at  the  other  end  of  the  tube. 
I  find  there  is  something  wrong  here — the  mercury  in  the  ther- 
mometer has  risen  several  degrees.  I  knew  this  was  rather  a  crude 
arrangement  for  illustrating  this  very  beautiful  and  interesting  part 
of  our  subject,  but  I  hoped  it  would  assist  me  a  little  in  conveying  to 
you  the  idea  I  desired  to  impress  upon  your  minds.  I  find,  however, 
that  it  is  scarcely  delicate  enough  to  illustrate  perfectly  what  I  wanted 
to  show. 

But  this  increased  temperature  is  not  owing  to  the  effect  of  radiant 
heat  on  the  air  coming  from  the  far  end,  for  I  find  by  the  heat  at  the 
top  of  the  pipe,  between  the  heated  ball  and  this  ascending  pipe,  I, 
and  by  the  current  of  heated  air  on  the  side  next  the  ball,  that  there 
is  a  current  of  circulating  air  that  has  been  heated  by  coming  into 
immediate  contact  with  the  hot  ball. 

I  designed  this  smaller  tube,  k,  to  carry  off  the  air  thus  heated,  but  it 
appears  to  be  too  small. 

We  ought  to  have  had  a  piece  of  rock-salt  to  have  closed  the  end 
of  this  tube,  so  that  the  radiant  heat  would  have  passed  through 
without  allowing  any  circulation  of  heated  air,  but  I  was  unable  to 
find  such  a  piece.  But  Professor  Tyridall,  in  his  lectures  before  the 
Royal  Institute  of  Great  Britain,  gives  the  results  of  a  large  number 
of  very  accurate  and  beautiful  experiments  tried  for  the  purpose  of 
determining  whether  the  forty-five  miles  of  atmosphere  surrounding 
the  earth  absorbed  any  of  the  sun's  rays,  and  if  so,  how  much  ? 

These  experiments  prove,  in  the  most  conclusive  manner,  that  dry 
pure  air  is  almost  a  perfect  non-absorbent  of  radiant  heat.  Thus,  were 
the  air  entirely  dry  and  pure,  the  whole  forty-five  miles  through 
which  the  sun's  rays  have  to  pass,  would  absorb  a  very  small  fraction 
thereof,  so  that  in  the  length  of  our  tube  it  would  be  but  an  exceed- 
ingly small  fraction  pf  one  degree,  that  is,  for  pure  dry  air. 

But  is  the  air  of  this  room  pure  and  dry  ?    Very  far  from  it. 

Professor  Tyndall  found  that  the  moisture  alone  in  the  air  of  an 
ordinary  room,  absorbed  from  fifty  to  seventy  times  as  much  of  the 
radiant  heat  as  the  air  does.  Air  and  the  elementary  gases — oxygen, 
hydrogen  and  nitrogen — have  no  power  of  absorbing  radiant  heat,  but 
the  compound  gases  have  a  very  different  effect;  for  instance,  olifiant 
gas  absorbs  7950  times  as  much  as  air;  ammonia,  7260;  sulphurous 
acid,  8800  times.  Perfumes,  also,  have  a  wonderful  power  of  absorb- 
ing radiant  heat. 

The  moisture  in  the  air,  however,  is  of  the  greatest  practical 


23 

importance  in  various  ways.  It  is  the  great  governor  or  regulator 
or  conservator  of  heat;  it  absorbs  it  and  carries  it  from  point  to 
point  and  into  places  where  the  direct  rays  of  the  sun  could  not  get ; 
it  is  like  a  soft  invisible  blanket  constantly  wrapped  around  us,  which 
protects  us  from  too  sudden  heating  or  too  sudden  cooling. 

Professor  Tyndall,  speaking  of  the  moisture  in  the  air,  says:  "Re- 
garding the  earth  as  a  source  of  heat,  no  doubt  at  least  ten  per  cent, 
of  its  heat  is  intercepted  within  ten  feet*  of  its  surface."  He  also 
says:  "The  removal  for  a  single  summer's  night  of  the  aqueous 
vapor  from  the  atmosphere  which  covers  England,  would  be  attended 
by  the  destruction  of  every  plant  which  a  freezing  temperature  could 
kill. 

"In  Sahara,  where  the  soil  is  fire  and  the  wind  is  flame,  the  re- 
frigeration is  painful  to  bear." 

And  in  many  of  our  furnace-heated  houses,  we  have  an  atmosphere 
very  similar  in  point  of  dryness  to  that  of  Sahara,  but  more  impure. 

The  foregoing  remarks  in  regard  to  the  impossibility  of  heating 
air,  apply  especially  to  radiant  heat.  Air  does  become  heated,  but 
in  a  different  manner  ;  it  is  heated  by  each  individual  particle  or  atom 
coming  in  immediate  contact  with  some  hotter  substance.  See  what 
a  wonderful  provision  for  creating  a  constant  circulation  of  the  air. 
The  sun's  rays  pass  through  it  without  heating  it,  but  they  heat  the 
surface  of  the  earth  at  the  very  bottom  of  the  ocean  of  air  ;  this,  in  its 
turn,  heats  the  air  by  each  individual  atom  coming  in  immediate  con- 
tact with  these  hotter  substances,  expanding  them  so  that  they  must 
rise,  thus  enabling  the  colder  and  heavier  particles  to  rush  in  and 
take  their  places.  With  this  great  universal  moving  cause,  in  con- 
nection with  the  innumerable  minor  causes  resulting  from  the  very 
different  absorbing,  radiating  and  reflecting  powers  of  various  sub- 
stances, it  becomes  almost  impossible  for  the  air  to  be  entirely  and 
absolutely  at  rest,  even  in  the  most  minute  crack  or  cranny,  or  bottle 
corked  air-tight. 

Now,  to  apply  these  principles  to  every-day  life,  to  the  heating  and 
ventilation  of  our  houses,  taking  the  open  fire  first,  we  find  that  it  acts 
like  the  sun,  heating  exclusively  by  direct  radiation.  The  rays  of 
heat  fall  upon  the  sides  of  the  room,  the  floor  and  ceiling,  and  the 
solid  substances  in  the  room,  which  thus  become  partially  heated,  and 
in  their  turn  become  secondary  radiators.  This  radiant  heat  from 
the  fire  does  not  heat  the  air  in  the  room  at  all,  but  the  air  becomes 
partially  warmed  by  coming  in  immediate  contact  with  the  sides  of 
the  room,  the  furniture,  &c. 


24 

One  great  reason,  therefore,  why  an  open  fire  is  so  much  more 
wholesome  than  any  other  means  of  artificial  heating,  is  because  it 
more  nearly  imitates  the  action  of  the  sun. 

The  rays  of  heat  fall  upon  our  bodies,  heating  them,  while  it 
leaves  the  air  cool,  concentrated  and  invigorating  for  breathing. 
The  bright  glow  of  an  open  fire  has  a  very  Cheering  and  animating 
effect.  It  produces  a  very  agreeable  and  heaLhy  excitement. 

It  is  not  improbable  that  future  careful  investigations  may  prove 
that  there  is  an  important  change  takes  place  in  the  electric  or  ozonic 
condition  of  air  as  it  passes  over,  or  in  contact  with,  hot  iron,  which 
does  not  occur  to  the  air  of  a  room  heated  by  the  open  fire. 

The  air  in  a  room  heated  by  an  open  fire  can  scarcely  become  stag- 
nant, because  that  fire  must  necessarily  be  constantly  drawing  a  con- 
siderable amount  of  air  from  the  room  to  support  combustion,  the 
place  of  which  will  be  supplied  by  other  air,  and  here  is  where  one 
of  the  greatest  inconveniences  arises  in  the  use  of  the  open  fire ;  if 
the  air  entering  to  supply  this  exhaustion  comes  in  at  a  crack  of  the 
door  or  window,  on  the  opposite  side  of  the  room,  and  that  air  is 
cold,  say  10°  or  15°  above  zero,  it  flows  across  the  floor  to  the  fire, 
chilling  the  feet  and  backs  of  those  sitting  in  its  track.  It  is  quite 
possible  to  roast  a  goose  or  round  of  beef  in  front  of  a  fire,  while  the 
air  flowing  by  it  into  the  fire  is  freezing  cold.  This  should  be  reme- 
died by  having  the  air  flowing  in  partially  warmed  before  it  enters, 
say  to  a  temperature  of  40°  to  50°,  either  by  having  the  halls  over- 
flowed by  partially  warmed  air,  and  opening  a  door  into  it,  or  by 
admitting  the  air  to  enter  around  the  back  of  the  fire-place,  as  Dr. 
Franklin  arranged  it. 

Thus,  while  an  open  fire  is  the  healthiest  known  means  of  heating 
a  small  room,  and  should  be  in  the  family  sitting-room  of  every 
house,  and  in  offices  arid  other  places  where  the  occupants  are  at 
liberty  to  move  closer  or  further  from  the  fire  at  pleasure,  yet  it  is 
entirely  unsuitable  for  a  large  building,  or  for  rooms  where  many 
persons  are  assembled,  and  have  fixed  seats,  similar  to  a  school, 
lecture-room,  factory,  &c. 

A  stove  in  a  room  heats  both  by  direct  radiation  and  by  heating 
the  air  that  comes  in  immediate  contact  with  it. 

But  our  latest  styles  of  elegant  new  patent  gas-consuming  air-tight 
stoves,  require  so  small  an  amount  of  air  to  support  combustion,  that 
there  is  a  strong  probability  of  the  occupants  of  a  room  thus  heated 
smothering  to  death  for  want  of  fresh  air,  sooner  or  later,  and  gene* 
rally  the  former. 


25 

But  a  stove,  if  properly  used,  creates  a  comfortable  and  wholesome 
atmosphere,  and  is  one  of  the  most  economical  means  of  heating  now 
known.  There  should  always  be  a  separate  pipe  for  introducing  the 
fresh  air  from  the  external  atmosphere,  which  fresh  and  cold  air  should 
be  discharged  on  or  near  the  top  of  the  stove.  And  if  this  supply  of 
fresh  air  is  abundant,  with  a  constant  evaporation  of  moisture  suffi- 
cient to  compensate  for  the  increased  capacity  therefor  due  to  the 
additional  heat  given  it,  and  an  opening  into  a  heated  flue  near  the 
ceiling,  to  be  opened  in  the  evening  when  the  gas-lights  are  burning, 
or  when  the  room  is  too  hot,  and  kept  shut  at  all  other  times,  with 
another  opening  into  a  heated  flue  on  a  level  with  the  floor,  which 
should  be  kept  always  open  to  carry  off  the  cold,  heavy  foul  air  from 
the  floor— a  stove  thus  arranged  for  many  small  isolated  rooms,  makes 
one  of  the  most  economical  as  well  as  most  comfortable  and  wholesome 
means  of  heating  at  our  command.  It  combines  the  three  great  essen- 
tials necessary  for  comfort  and  health — warmth,  partially  by  direct 
radiation,  fresh  air  and  moisture.  But  neither  the  open  fire  nor  the 
stove,  as  desirable  as  they  may  be  in  many  small  rooms,  are  suitable 
for  large  rooms,  especially  where  many  persons  are  assembled.  Heat- 
ing principally  by  circulating  warmed  air,  or  in  combination  with  direct 
radiation  from  exposed  pipes  filled  with  steam  or  hot  water,  is  in  such 
cases  more  convenient. 

It  is  in  connection  with  this  system  of  heating  by  circulating  warm 
air,  that  the  erroneous  views  in  relation  to  ventilation  generally  en- 
tertained by  the  public,  produce  the  most  injurious  effects. 

The  special  points  to  be  borne  in  mind  in  considering  this  subject 
are  that,  when  in  motion,  warmer  air  rises  and  colder  air  falls;  but 
when  at  rest,  the  stratums  of  air  of  different  temperatures  arrange 
themselves  horizontally.  • 

One  other  thing :  we  must  remember  temperature  has  nothing  to  do 
with  the  purity  or  impurity  of  the  air.  The  pure  air  entering  a  room, 
is  sometimes  colder  than  the  average  temperature  of  the  room,  and 
falls  to  the  floor,  forcing  the  warmer,  and,  in  that  case,  fouler  air  to 
the  upper  part  of  the  room. 

But  frequently,  in  winter,  the  fresh  air  enters  warmer  than  the 
average  temperature  of  the  room,  and  rises  to  the  ceiling,  and  flows 
across  the  room  above  the  colder  and  fouler  air  that  has  been  longer 
in  the  room.  You  must  not  forget  the  experiments  in  our  first  lec- 
ture, showing  that  the  breath  in  an  ordinary  room,  of  a  temperature 
of  70°,  fell  to  the  floor  instead  of  rising  to  the  ceiling.  I  propose 


26 

illustrating  this  part  of  our  subject,  by  using  a  little  glass  room 
to  show  the  movements  of  air  of  different  temperatures.  We  can 
either  use  air  of  different  temperatures,  showing  the  motion  of  the  va- 
rious currents  by  a  little  smoke ;  or,  as  the  laws  governing  the  circu- 
lation of  liquids  of  different  densities  are  so  similar,  and  by  the  use 
of  a  little  coloring  matter  will  express  to  an  audience  of  this  kind 
more  promptly  and  clearly  the  ideas  which  we  wish  to  convey,  we 
therefore  propose  using  the  different  colored  liquids  this  evening. 

The  colors,  of  course,  have  nothing  to  do  with  the  densities,  but 
are  merely  used  as  a  convenient  method  of  designation ;  the  red  repre- 
senting heat  or  rarity,  and  blue,  coldness  or  density. 

The  room  is  now  filled  with  clear  water,  slightly  blue,  to  represent 
cold,  and  a  little  salt,  which  makes  it  a  little  more  dense  than  fresh 
water.  Now,  I  will  let  in  at  the  top  a  little  fresh  water,  colored  red  by 
cochineal,  to  represent  heat,  and  by  making  a  similar  opening  on  the 
opposite  side  for  its  escape,  you  will  be  able  readily  to  see  in  what  direc- 
tion it  moves.  There,  see  it  entering — see  how  it  flows  directly  across 
the  top  of  the  room,  and  escapes  at  the  opening  on  the  opposite  side. 
You  see  it  disturbs  the  lower  and  colder  parts  of  the  room  but  very  little. 
Thus  a  large  flow  of  pure  fresh  warm  air  might  be  going  through  a 
room  all  day,  and  be  entirely  wasted,  neither  warming  nor  ventilating 
it.  Fortunately,  there  are  but  few  buildings  arranged  in  quite  so 
absurd  a  manner  as  this.  I  believe  it  was  tried  in  the  House  of 
Lords,  on  the  erection  of  the  new  Houses  of  Parliament,  but,  of 
course,  failed.  I  think  they  still  adhere  to  it  in  some  of  the 
wards  of  some  Insane  Asylums,  where  they  depend,  I  suppose,  upon 
the  excitement  of  the  patients  to  keep  themselves  warm  and  the  air 
stirred  up.  I  also  noticed  this  arrangement  in  a  new  building  just 
being  finished,  a  few  years  since,  at  Yale  College.  The  architects  of 
that  building  had  probably  been  impressed  with  the  dreadful  effects 
upon  the  health  of  students  of  the  air  from  our  ordinary  hot  air  fur- 
naces, and  thought  they  would  avoid  all  such  danger.  I  think,  how- 
ever, it  would  have  answered  their  purpose  just  as  well,  and  been 
much  more  economical,  to  have  placed  the  furnaces  at  the  coal  mines, 
and  saved  the  trouble  and  expense  of  carrying  the  coal  so  far.  I 
expect  they  have  made  other  arrangements,  probably,  by  this  time. 

We  will  now  close  the  opening  at  the  top  for  the  inlet  of  the  fresh 
warmed  air,  and  open  a  valve,  so  as  to  allow  it  to  flow  in  at  the  bot- 
tom. We  will  allow  the  opening  at  the  top  for  the  outlets?  thefoul(?) 
air  to  remain  as  before,  (see  Fig.  1,  Lithograph  plates.)  This  is 


Fig.3 


-V.-.. 


I 


27 

quite  an  improvement ;  it  agitates  the  air  much  more  than  the  other, 
and  by  going  and  standing  directly  over  the  register,  you  can  always 
get  in  the  current  of  fresh  warm  air.  But  you  see  to  what  a  very 
small  portion  of  the  room  the  heated  air  is  confined,  rising  in  one 
perpendicular  column  directly  to  the  ceiling,  and  then  flowing  hori- 
zontally along  the  ceiling  to  the  outlet.  How  little  it  disturbs  the 
main  portions  of  the  room,  especially  the  lower  and  occupied  part. 

I  hope  you  will  notice  that  this  illustrates  the  popular  notions  of 
ventilation.  I  suppose  three-fourths  of  all  the  buildings  in  this  coun- 
try, or  in  Europe,  where  any  attempts  at  artificial  ventilation  have 
been  made,  are  thus  arranged.  Dr.  Franklin  knew  better,  and  made 
a  much  more  perfect  arrangement  than  this.  But  we  are  probably 
mostly  indebted  to  that  very  able  and  enthusiastic  advocate  of  venti- 
lation, Dr.  Reid,  for  this  popular  opinion.  The  whole  of  the  plan 
that  he  advocated  is  but  little  understood  by  the  public.  He  assumed 
that  the  natural  warmth  of  the  body  created  an  ascending  current 
around  us,  and  caused  the  breath  to  rise  towards  the  ceiling,  and 
consequently,  in  all  artificial  arrangements,  it  was  best  to  endeavor 
to  imitate  this  natural  movement  of  the  air.  And  to  overcome  the 
great  practical  difficulty  we  see  here  exhibited,  of  the  fresh  warm  air 
flowing  through  the  room,  and  disturbing  so  small  a  portion  of  it,  he 
proposed  making  the  whole  floor  one  register,  and  thus  have  an  as- 
cending column  over  the  entire  room.  For  this  purpose,  the  floors  in 
the  Houses  of  Parliament  were  perforated  by  hundreds  of  thousands  of 
gimlet  holes,  and  the  whole  cellar  made  a  hot  air  chamber.  This  was 
a  magnificent  idea,  and,  I  believe,  in  some  few  instances,  where  fully 
carried  out,  has  given  a  good  degree  of  satisfaction  ;  but  it  is  always 
difficult  to  adjust  the  opening  and  the  pressure  so  as  to  cause  an  even 
flow  over  so  large  a  surface,  and  at  the  same  time  to  be  so  gentle  as 
not  to  be  offensive  to  those  with  whom  it  comes  in  contact.  But  this 
thorough  diffusion  cannot  be  conveniently  applied  in  one  case  in  a 
thousand.  It  must  necessarily  be  always  very  extravagant,  as  it  will 
constantly  require  a  great  amount  of  air  to  insure  a  thorough  circula- 
tion through  all  parts  of  the  room.  I  wish,  therefore,  most  emphati- 
cally, to  condemn  all  systems  rely  ing  upon  openings  in  the  ceiling  for  the 
escape  of  the  foul  air, while  depending  upon  the  circulation  of  warmed 
air  for  obtaining  the  necessary  additional  warmth.  In  practice  they 
are  universally  closed  in  winter,  for  the  purpose  of  keeping  warm, 
and  as  such  openings  have  been  so  generally  considered  {.he only  ones 
necessary  for  the  proper  ventilation  of  a  room,  and  as  they  had  to  be 


23 

shut  in  winter,  just  when  artificial  ventilation  was  most  necessary,  it 
has  created  a  very  strong  prejudice  in  the  popular  mind  against  all 
ventilation. 

The  result  of  the  advocacy  of  these  impracticable  theories  by  so 
many  able  and  learned  men,  (most  physicians  writing  upon  this  sub- 
ject have  adopted  them,)  has  been  the  shutting  up  of  many  thousands 
and  tens  of  thousands,  till  they  have  smothered  to  death. 

The  ravages  of  consumption  and  the  excessive  infantile  mortality, 
and  the  many  diseases  resulting  from  foul  air  poisons,  are  in  a  great 
measure  due  to  the  general  advocacy  of  these  false  theories.  As  I 
have  before  said,  Dr.  Franklin  knew  better  than  this,  and  had  we 
been  contented  to  have  followed  his  simple  practical  advice,  instead 
of  being  dazzled  by  the  splendid  theories  of  others,  thousands  of  our 
friends  would  now  be  with  us  who  died  long  since  for  the  want  of 
fresh  air. 

Now,  let  us  see  how  Dr.  Franklin  says  a  room  ought  to  be  venti- 
lated. He  says,  "  the  fresh  air  entering,  becoming  warmed  and  spe- 
cifically lighter,  is  forced  out  into  the  rooms,  rises  by  the  mantel-piece 
to  the  ceiling,  and  spreads  all  over  the  top  of  the  room,  whence,  being 
crowded  down  gradually  by  the  stream  of  newly  warmed  air  that  fol- 
lows and  rises  above  it,  the  whole  room  becomes  in  a  short  time 
equally  warmed."  This  is  the  principle  upon  which  his  celebrated 
Franklin  stove  was  arranged.  Now,  let  us  see  if  we  can  arrange  our 
little  glass  house  so  as  to  illustrate  this.  We  will  first  fill  it  with 
what  we  call  our  cold  air,  and  will  close  the  outlet  at  the  top,  and 
take  out  the  fire-board.  Now,  as  I  let  in  the  warm  fresh  air,  it 
rises  immediately  to  the  top,  as  before,  and  flows  across  the  ceiling, 
but  as  it  cannot  escape  there,  it  forces  the  cold  air  down,  and  causes 
it  to  flow  out  at  the  fire-place.  See  how  quickly  the  whole  room  is 
filled  with  the  fresh  warmed  air.  Ah  !  I  see  I  am  a  little  too  fast — 
there  appears  to  be  a  stratum  of  a  foot  or  two,  lying  on  the  floor, 
that  is  not  disturbed  yet.  It  flows  out  at  the  top  of  the  fire-place, 
and  therefore  does  not  reach  to  the  floor.  This  is  frequently  the 
cause  of  cold  feet  and  much  discomfort.  "We  will  make  the  opening 
directly  at  the  floor,  (see  Fig.  2,  Lithograph  plate,)  and  that  forces  all 
the  cold  air  out,  warming  and  ventilating  the  whole  room.  Here  is 
the  whole  problem  solved  in  the  most  beautiful  and  simple  manner. 
And  you  may  exclaim,  as  you  see  the  simplicity  and  perfect  working 
o(  this,  how  came  any  one  ever  to  think  of  anything  else. 

Here,  again,  you  see  the  value  of  that  most  excellent  and  valuable 


29 

of  household  arrangements,  the  open  fire-place ;  even  without  the  fire 
it  serves  a  most  important  purpose. 

"We  must  not  forget,  however,  that  there  are  other  circumstances 
in  which  it  will  not  do  to  depend  on  the  fire  place  alone  for  ventilation. 
Now,  by  leaving  the  fire-place  open,  just  as  it  is,  and  the  room  full 
of  warm  air,  we  will  simply  change  the  condition  of  the  air  supplied, 
and  allow  cold  air  to  flow  in  at  the  bottom  instead  of  the  top.  (See  Fig. 
3.)  There,  you  see  the  fresh  cold  air  simply  falls  to  the  bottom  and 
flows  across  the  floor,  without  disturbing  the  upper  part  of  the  room 
at  all.  It  acts  just  the  reverse  of  the  hot  air  let  in  and  taken  out  at 
the  top  of  the  room.  When  you  are  ventilating  a  room  by  opening  a 
window,  therefore,  it  is  often  necessary  to  open  it  at  the  top ;  but 
remember  when  you  are  ventilating  by  doors  and  windows,  (which  are 
the  great  natural  ventilators,)  they  are  an  entire  substitute  for  flues — 
flues  are  then  of  no  account.  All  windows,  therefore,  ought  to  be 
made  to  loioer  from  the  top,  and  all  ventilating  flues  ought  to  be  made 
to  open  at  the  bottom  of  the  room. 

I  have  noticed  another  very  interesting  feature  in  regard  to  the 
circulation  of  liquids  of  different  densities ;  for  instance,  suppose  we 
fill  our  little  room  half  full  with  salt  water,  and  the  remainder  with 
fresh  water,  we  will  now  apply  a  spirjt  lamp  to  the  bottom  of  the 
room.  As  the  salt  water  becomes  heated  it  rises  rapidly,  yet  not  to 
the  top  of  the  room,  but  only  half-way,  or  to  the  top  of  the  denser 
liquid,  and  then  spreads  across  the  room  horizontally.  Thus  the  salt 
water  will  keep  up  a  rapid  circulation,  and  may  be  heated  almost 
to  a  boiling  temperature  underneath,  and  without  heating  or  dis- 
turbing, the  cold  fresh  water  above.  I  have  tried  some  very  beautiful 
experiments  of  this  kind  with  a  number  of  liquids  of  different  densi- 
ties in  the  same  vessel.  Gases  of  different  densities  are  probably 
influenced  in  a  similar  manner  by  the  application  of  heat.  And  here 
we  see  the  value  of  that  beautiful  law  of  the  diffusion  of  gases,  by 
which  each  gas,  no  matter  what  its  density,  is  equally  diffused  in  all 
directions  through  the  other  gases,  independent  of  temperature. 

.  I  desire  to  call  your  attention  this  evening  to  one  other  distinct 
system  of  heating — I  mean  that  very  convenient,  economical,  cleanly 
and  FASHIONABLE  system  of  heating  by  direct  radiation  from  steam- 
'pipes. 

As  steam  has  become  such  a  common  article  in  all  large  buildings, 
both  for  power  and  as  a  convenient  means  of  distributing  heat,  most 
large  buildings  are  thus  heated;  and  as  a  perfectly  air-tight  building 


80 

can  be  very  easily  heated  thus,  and  as  most  persons  are  too  ignorant 
or  too  careless  to  provide  a  separate  and  distinct  supply  of  fresh 
air  simply  for  ventilation  alone,  the  consequence  is,  that  this  system, 
thus  so  shamefully  abused,  is  probably  drying  up  more  talent  and 
killing  more  business  men  in  our  cities  than  any  other  system  in  ex- 
istence. This  applies  especially  to  the  editorial  rooms  of  nearly  every 
one  of  our  leading  newspapers  and  publishing  houses.  They  use 
steam  for  driving  their  beautiful  printing  presses,  and  the  heating  and 
ventilation,  or  rather,  the  entire  want  of  ventilation,  in  their  offices, 
would  indicate  that  they  think  that  the  same  power  that  drives  their 
presses,  to  do  the  printing  so  nicely,  is  entirely  sufficient  to  drive 
them  to  write  the  original  articles  for  the  printer,  and  that  they  have 
no  more  need  of  fresh  air  than  their  presses. 

You  may  think  that  I  am  certainly  mistaken  that  so  intelligent  a  class 
of  the  community,  who  are  building  such  splendid  fire-proof  build- 
ings, such  perfect  palaces  of  iron  and  stone  and  marble,  as  our  news- 
paper establishments  are  building  in  New  York,  Philadelphia  and 
other  large  cities,  would  never  make  such  a  blunder  as  to  omit  pro- 
viding the  most  abundant  supply  of  pure,  fresh  air  to  every  employe 
in  their  establishments,  and  at  all  times,  both  in  summer  and  winter. 

Should  there  be  any  one  present  thus  doubtful,  I  wish  he  would 
undertake  to  get  any  one  of  our  enterprising  newspaper  establishments 
to  publish  in  their  paper  an  accurate  intelligible  account  of  their  sys- 
tem of  ventilation,  illustrating  clearly  the  known  quantity  of  pure, 
fresh  air  delivered  within  using  distance  of  each  one  of  the  editors 
and  employes. 

I  think  he  would  soon  come  to  the  same  conclusion  I  have,  that  th*. 
advice  of  the  minister  to  his  congregation  would  be  very  applicable 
io  them— "Always  do  as  I  «a^,  but  never  do  as  I  do." 


31 


LECTTJKE  III. 

In  my  first  lecture,  I  endeavored  to  show  how  much  we  were  suf. 
fering  from  the  effects  of  foul  air,  and  the  advantages  to  be  gained  by 
supplying  ourselves  all  the  time  with  pure  air.  Because  we  must 
first  feel  that  there  is  something  to  be  gained  before  we  will  make 
any  great  effort  towards  obtaining  a  given  result. 

In  my  second  lecture  we  considered  the  general  principles  governing 
the  circulation  of  air,  the  courses  of  its  movements,  the  manner  of  the 
action  of  heat  upon  different  kinds  of  substances,  which  creates  a  con- 
stant, ceaseless  motion  of  the  air,  in  all  places,  from  the  minutest 
corked  bottle  to  the  vast  currents  that  sweep  over  the  face  of  the  earth. 

Now,  having  learned  the  necessity  for  pure,  fresh  air,  and  studied 
the  general  laws  governing  its  circulation,  let  us  apply  these  princi- 
ples to  every-day  life.  To  every-day  life  ?  I  should  say  everj-hour 
life — nay,  every  moment  of  our  lives  ;  for  twenty  times  every  minute 
of  our  entire  life,  from  the  cradle  to  the  grave,  do  we  breathe  what 
ought  to  be  pure  air.  Is  it  always  pure  ? 

If  we  breathe  one  single  breath,  in  the  entire  day,  of  impure  air,  it 
will  weaken  us,  deduct  from  our  capacity  to  attend  to  our  daily  duties, 
and  shorten  our  lives,  in  exact  mathematical  proportion  to  the 
amount  of  impurity  in  that  one  single  breath.  Now,  we  breathe 
twenty  times  every  minute,  twelve  hundred  times  every  hour,  twenty- 
eight  thousand  times  every  day,  and  nothing  but  absolute  and  per- 
fectly pure  air  answers  the  exact  requirements  of  perfect  health. 

Well,  you  may  ask,  at  first  thought,  if  fresh  air  is  such  a  panacea 
for  all  evils,  and  there  is  such  an  abundance  of  it  out  of  doors,  why 
not  breathe  it,  and  always  enjoy  perfect  health  ? 

Think  one  moment.  I  eat  my  breakfast  in  the  morning,  generally 
refreshed  by  a  night  of  good  sound  sleep,  (for  I  sleep  with  my  windows 
open.)  Immediately  a-ft?r  breakfast,  I  enter  the  cars  to  come  to  the 
city.  What  a  smell  comes  from  the  car  as  the  door  is  opened !  and 
unless  I  wish  to  incur  the  displeasure,  or  provoke  the  indignation,  of 
almost  every  passenger,  by  opening  a  window,  I  am  obliged  to  sit  in 
that  foul,  offensive  atmosphere,  and  breathe  the  poisonous  exhalations 
from  my  own  lungs,  and  that  from  dozens  of  others,  some  of  them, 
it  may  be,  badly  diseased,  (most  persons'  lungs  are  diseased  in  this 
country,  from  breathing  foul  air,  and  many  other  diseases  besides 
consumption  are  produced  thereby.) 

Thus,  in  one  half  hour,  I  have  inhaled  six  hundred  times  of  this 


32 

foul  and  poisonous  air,  and  the  blood  has  carried  it  to  every  portion 
of  my  body,  so  that  my  entire  system  is  completely  saturated,  poi- 
soned, yes,  thoroughly  poisoned  by  it,  from  the  crown  of  my  head  to 
the  soles  of  my  feet. 

And  thus  is  the  day  commenced.  Your  blood  is  thoroughly  poi- 
soned before  your  breakfast  is  digested ;  for  your  breakfast  will  no 
more  digest  without  pure  air  than  the  coal  in  your  stove  will  burn 
without  it.  You  are  subjected  to  headache,  dyspepsia,  and  a  half 
dozen  other  aches  and  pains,  and  are  tired  out  long  before  night. 
And  thus  you  are  killed  long  before  you  would  die  if  you  breathed 
pure  air  only. 

And  am  I  relieved  from  the  difficulty  when  I  arrive  in  the  city? 

Start  to-morrow  morning  at  the  Delaware  River,  on  Arch  or  Wal- 
nut Streets,  or  any  other  street,  and  go  to  the  Schuylkill.  Inqufre  of 
every  individual,  in  office,  store,  dwelling  or  factory,  if  he  knows 
whether  he  had  pure  air  to  breathe  all  day,  or  whether  he  can  tell 
you,  with  any  degree  of  accuracy,  how  pure  the  air  was  in  the  room 
he  occupied  for  any  hour  of  that  day. 

I  fully  believe  there  is  not  one  in  ten — no,  not  one  in  a  hundred — 
of  the  most  intelligent  men  in  that  entire  street,  doctor,  lawyer, 
architect,  or  any  other,  that  can  give  you  an  accurate  account  of  the 
condition  of  the  air  breathed  during  any  one  hour  of  the  day.  That  is 
not  all.  There  is  scarcely  one  in  a  hundred  that  can  satisfy  you,  by 
an  intelligent  description,  of  the  means  usbd  for  providing  it: 

First — Assuming  the  air  outside  to  be  pure,  that  there  was  a  con- 
stant, positive  and  sufficient  supply  of  that  outside  air  introduced. 

Secondly — That  that  pure  air  was  not  deteriorated  by  overheating, 
or  contaminated  by  being  mixed  with  the  poisonous  gases  of  the 
burning  coal. 

Thirdly — That  there  was  sufficient  moisture  added  to  it  to  com- 
pensate for  its  increased  capacity  for  moisture,  due  to  its  expansion 
by  the  additional  heat  given  to  it,  (which  is  a  very  important  thing.) 

Fourthly — That  there  was  any  accurate,  positive  means  provided 
for  insuring  the  fresh  air  to  be  brought  within  reach  of  the  lungs 
of  those  for  whom  it  was  intended. 

And,  lastly — That  there  was  a  positive  means  provided  for  the 
removal  of  all  the  poisoned  air  thrown  from  the  lungs,  so  that  none 
could  possibly  be  re-breathed. 

No ;  you  will  find  them  in  close,  unventilated  offices,  in  close 
factories,  in  almost  air-tight  dwellings.  In  the  large  stores  they  do 
better. 


33 

The  air  is  very  commonly  overheated,  it  is  often  mixed  with  im- 
purities, and  very  seldom  supplied  with  a  proper  amount  of  additional 
moisture. 

The  air  is  often  so  dry,  that  in  a  few  minutes'  conversation  the 
linings  of  the  air-passages  to  your  lungs  become  parched  and  husky, 
producing  irritation  and  a  feverish  condition  of  the  system.  And  even 
in  this  room,  to-night,  do  you  see  any  opening  at  your  feet,  connected 
with  a  heated  flue,  for  drawing  the  foul  air  from  the  floor  as  fast  as 
thrown  from  your  lungs  ?  I  believe  there  is  not  a  square  inch  pro- 
vided for  that  purpose. 

Or,  do  you  see  any  escape  immediately  above  the  gas-lights,  for 
carrying  off  the  burned  air  while  hot  enough  to  escape  ?  Not  one. 
There  are  two  or  three  openings,  I  think,  in  the  back  part  of  the 
room,  just  at  the  ceiling,  but  for  your  breath  to  get  there,  it  must 
rise  -and  pass  by  the  zone  of  respiration,  and  much  of  it  be  again 
re-breathed;  and  the  products  of  combustion,  as  we  have  seen,  would 
cool  sufficiently  to  fall  to  the  floor  long  before  they  reached  that 
point. 

I  take  the  liberty  of  calling  your  attention  to  this  with  more  free- 
dom, because  it  does  not  indicate  any  special  inattention  on  the  part 
of  the  Managers.  It  is  not  an  exceptional  case,  but  it  is  the  rule. 
It  is  the  popular  opinion  of  the  proper  means  of  ventilation. 

Go  with  me,  if  you  please,  to  that  magnificent  building,  completed 
but  a  few  years  since,  at  a  cost  of  half  a  million  of  dollars,  and  given 
by  its  noble  and  generous  founder  to  the  city  of  New  York.  You 
will  notice,  inscribed  above  the  entrance,  cut  in  the  solid  stone,  "To 
the  Arts  and  Sciences."  Look  in  this  reading-room — perhaps  the 
most  useful  and  most  appreciated  of  any  public  reading-room  in  the 
United  States.  See  the  large  numbers  of  honest,  industrious  me- 
chanics, snatching  an  hour  from  their  labors,  to  look  over  the  current 
literature  of  the  day.  Here,  certainly,  we  shall  find  the  most  perfect 
arrangement  for  heating  and  ventilation  that  our  knowledge  of  the 
arts  and  sciences  could  suggest.  Let  us  see  the  arrangements  for 
bringing  in  the  fresh  air,  for  warming  it  in  cold  weather,  and  for  re- 
moving the  foul  air. 

What !  no  provision  for  a  regular  supply  of  fresh  air  ?  Not  one 
foot,  not  one  inch — neither  are  there  any  regular  flues  for  the  removal 
of  the  foul  air.  And  this  most  remarkable  condition  of  things  is  but 
repeated  in  the  magnificent  hotels,  marble  palaces  used  as  offices,  and 
in  many  of  the  new  and  splendid  colleges ;  and,  we  might  almosft 
c 


34 

say,  in  all  other  buildings  throughout  the  length  and  breadth  of  our 
land. 

Thus  you  see  how  difficult  it  is  for  one  to  mingle  freely  in  the 
society  of  his  fellow-men,  under  existing  circumstances,  without  being 
subjected  to  being  poisoned  by  foul  air.  In  going  from  here  to  my 
home,  to-night,  I  shall  have  to  ride  in  those  cars,  the  air  of  which  I 
dread  more  than  I  ever  dreaded  the  small-pox  or  cholera.  I  have 
been  in  hospitals  where  I  have  seen  much  of  both.  They  may  slay 
their  thousands,  but  foul  air  its  tens  of  thousands.  And  it  is  only 
when  I  get  to  my  room,  where  I  shall  probably  sleep  to-night  with 
two  windows  well  open,  allowing  the  unobstructed  breezes  of  half  a 
mile  of  open  country  to  sweep  through  my  chamber,  that  I  shall  feel 
entirely  secure  from  the  contaminating  influences  of  foul  air,  and 
enjoy  to  its  full  extent  the  greatest  of  God's  temporal  blessings  to 
man — pure  air. 

I  have  no  new  patent  idea  to  present  to  you,  which  shall  secure  to 
you  at  all  times  perfectly  pure  air,  without  any  further  trouble  on 
your  part.  There  are  no  two  constitutions  precisely  alike,  any  more 
than  there  are  two  human  faces,  or  two  handwritings,  and  there  are 
no  two  hours  in  our  entire  life  in  which  all  the  physical  conditions  of 
our  body  are  precisely  the  same.  It  would  be  just  as  absurd,  there- 
fore, to  go  to  a  ventilating  establishment,  and  tell  the  proprietor  to 
ventilate  your  house  or  office,  and  pay  the  bill  when  it  came  in,  and 
content  yourself  by  saying  :  "  Well,  I  am  glad  this  ventilating  busi- 
ness is  done  with.  I  have  got  my  house  ventilated,  and  the  bills 
paid,  and  I  am  glad  I  am  through  with  that  vexatious  business."  I 
say  this  would  be  just  as  absurd  as  it  would  be,  in  case  you  had  some 
pain  or  ache,  to  go  to  your  doctor  and  get  some  medicine,  and  therewith 
content  yourself,  and  say:  "Well,  I  am  glad  this  doctoring  business 
is  over  with;  I  have  been  dreading  it  all  my  life.  I  have  been  to  the 
doctor's  at  last,  have  been  doctored,  and  got  my  medicine  and  paid 
my  bill,  and  so  I  am  through  with  that  vexatious  business." 

No — you  must  first  feel  that  fresh  air  is  worth  taking  some  trouble 
to  obtain.  You  must  then  make  it  a  study  how  to  obtain  it  without 
chilling  or  overheating  your  body,  in  winter  and  in  summer,  at  night 
and  in  the  day  time,  when  you  are  lying  down  and  when  you  are  sit- 
ting up,  before  eating  and  after  eating,  before  exercising,  while  exer- 
cising, and  after  exercising — when  you  are  well  and  when  you  are 
sick,  when  you  are  alone  and  when  you  ai*e  in  the  crowded  cars,  or 
in  a  crowded  room,  in  wet  weather  and  in  dry,  and  for  the  ever 


35 

varying  changes  of  the  external  atmosphere — all  these  conditions 
require  separate  and  intelligent  thought. 

In  summer  we  depend  almost  exclusively  on  the  natural  movements 
of  the  air.  To  cause  the  air  to  move  is  then  the  great  matter.  We 
must  then  remember  that  the  great  masses  of  air  move  horizontally, 
not  perpendicularly.  Of  course,  there  are  many  little  disturbing  in- 
fluences, but  I  mean  the  great  mass  of  the  air  moves  over  the  surface 
of  the  earth  in  horizontal  strata.  You  can  see  this  by  the  smoke  of 
the  locomotive  on  the  prairie,  which  can  be  seen  sometimes  for  twenty 
or  thirty  miles,  stretching  along  just  above  the  horizon.  All  flues, 
therefore,  are  of  little  account  in  summer.  We  must  depend  on  open 
doors  and  windows.  Suppose  you  wish  to  ventilate  your  room  in  the 
morning,  the  air  outside  having  become  a  little  warmer  than  the  air 
inside,  and  the  upper  parts  of  the  window  only  lowered :  the  warmer 
air  would  flow  across  the  top  of  the  room,  leaving  the  air  undisturbed 
in  the  lower  and  colder  part.  In  this  case,  the  window  should  be  raised 
from  the  bottom,  or  a  door  opened  that  would  afford  an  escape  for 
the  air. 

But  again,  suppose  this  same  room  to  want  ventilating  in  the  even- 
ing. The  room  has  become  warm  through  the  day,  and  the  outside 
evening  air  is  cooler  than  the  room,  and  then,  if  you  raise  the  win- 
dows from  the  bottom  only,  the  cooler  air  will  flow  across  the  bottom 
of  the  room,  leaving  the  upper  part  undisturbed  and  foul. 

No  doubt  you  have  all  noticed,  frequently,  that  in  going  into  a 
room  in  the  evening,  when  your  heads  were  above  the  window  open- 
ing, it  would  be  quite  hot,  but  if  you  stooped  down  below  the  line  of 
the  open  window,  it  would  be  cool  and  pleasant.  All  windows  should 
be  made  to  lower  from  the  top,  to  meet  this  special  case.  If  you  are 
boarding,  or  are  so  unfortunate  as  to  be  put  in  a  room  where  the 
great  blunder  has  been  made  of  not  having  the  windows  to  lower,  go 
to  the  nearest  carpenter  shop  next  morning,  before  breakfast,  and 
got  a  chisel,  and  cut  six  or  eight  inches  off  the  little  strip  which 
supports  the  sash,  and,  with  a  gimlet,  bore  a  hole  directly  through 
the  sash,  on  both  sides,  and  with  a  nail  you  can  keep  the  sash  up  in 
its  place,  when  necessary.  I  have  had  hundreds,  yes,  I  suppose, 
thousands,  made  to  lower  this  way  in  the  hospitals. 

Motion,  motion  is  the  great  desideratum  in  summer.  You  have 
all  noticed,  no  doubt,  how  pleasant  it  is  to  go  into  a  cool  room,  like  a 
parlor,  that  has  been  kept  shut  up  on  a  hot  summer's  day ;  but  in  a 
short  time  it  begins  to  feel  oppressive,  and  it  is  more  comfortable  to 


36 


have  the  windows  open,  and  a  circulation  of  air,  even  if  it  should  be 
a  little  hotter  than  the  stagnant  cool  air. 

Never  sleep  with  closed  windows  in  summer.  It  is  in  winter,  how- 
ever, that  the  greatest  care  is  required  in  providing  a  constant  supply 
of  pure  air.  If  we  would  hut  accustom  our  minds  to  comprehend, 
readily  and  quickly,  that  cold  air  falls  and  warm  air  rises,  it  would 
assist  us  in  our  conclusions.  We  all  know  that,  of  course,  but  we  do 
not  practice  applying  it  readily  and  quickly  on  all  occasions. 

In  summer,  as  I  have  said,  the  air  moves  horizontally,  and  then 
windows  and  doors  are  the  great  means  of  ventilation;  but  as  cold 
weather  approaches,  we  must  keep  the  windows  shut,  excepting  when 
in  bed.  In  winter,  therefore,  we  must  resort  to  flues  for  the  means 
of  creating  a  circulation,  and  for  conveying  the  air  from  one  part  to 
another.  A  flue  is  simply  a  passage — a  communication — for  air  of 
different  temperatures.  A  flue  has  no  power  to  create  a  draught. 
If  the  air  within  is  colder,  it  will  have  the  power  to  fall;  if  warmer, 
it  will  be  driven  up. 

For  illustrating  this,  I  have  here  some  glass  tubes  about  two  feet 
long  and  two  inches  diameter.  This  one  (Fig.  8)  has  been  lying  on  the 

table  some  time,  and  I  suppose  is 
£'  very  nearly  the   temperature  of 

the  air  in  the  room.  I  have  here 
a  little  tin  box,  which  answers  for 
a  connecting  tube,  and  over  one  of 
the  openings  I  stand  this  tube, 
and  by  the  smoke  from  this  taper, 
first  held  at  the  top,  you  see 
there  is  no  current  down  the  tube. 
And  again,  by  holding  the  taper 
at  the  lower  opening,  you  see  there 
is  no  current  passing  up  the  flue. 
But  I  will  remove  that,  and  place  one  (Fig.  9)  over  the  same  opening 
that  is  warmer,  and  now  you  can  see  how  strongly  the  smoke  is  drawn 
down  through  this  lower  opening,  and  see  it  flowing  up  this  warm  flue, 
and  out  at  the  top. 

We  will  now  substitute  a  cold  flue  (Fig.  10).  This  condenses  the  air, 
and  it  falls  rapidly.  This  action  often  occurs  in  the  spring  and  early 
part  of  summer,  especially  in  the  morning,  as  the  external  air  becomes 
heated,  and  the  solid  mason-work  of  the  chimney  remains  cold,  causing 
a  descending  current,  which  is  often  noticeable  by  the  smell  of  soot 


37 


in  the  room.  We  will  now  add  this  tube,  of  the  same  temperature  as 
the  room  (Fig.  11),  to  see  if  the  additional  height  will  not  make  an 
ascending  current.  But  you  see  the  smoke  is  still  drawn  down,  the 


Fig.  9. 


Fig.  10. 


height  of  the  flue  adds  a  little  to  its  power,  but  the  difference  in  its 
temperature  is  the  controlling  force. 

We  will  now  place  another  tube  over  the  lower  opening  (Fig.  12). 
Just  see  what  a  wonderful  effect  that  has  !     Here  is  the  air  rushing 
Fig.  11.  Fig.  12. 


down  this  short  flue  and  up  the  two  cold  ones.  We  called  those  two 
first  pipes  cold,  but  our  ideas  of  heat  and  cold  are  simply  compara- 
tive ;  everything  is  warm,  or  has  heat  in  it.  Perhaps  some  of  us 
think  there  is  not  much  heat  in  the  air  when  it  comes  whistling  around 
our  ears  15°  or  20°  below  zero;  but  the  cold  rigid  chemist  will  still 


38 


Fig.  13. 


extract   many  degrees   of  heat   from    that.      We  must,  therefore, 
remember  that  absolute  temperature  has  nothing  to  do  with  the  air 
passing»up  or  down  a  flue — it  is  simply  comparative  temperature. 
Let  me  show  you  one  more  experiment.     Here  are  two  tubes  we 
have  had  heated;  as  you  see,   the 
smoke  rushes  up  them  rapidly.    But 
now    we   will   add    this    third   one 
(Fig.  13),  which  reverses  the   cur- 
rent at  once.    The  two  first  are  hot, 
taking  the  temperature  of  the  room 
as  tlie  standard,  but  the  third  one  is 
still  hotter. 

The  form  of  a  flue  has  but  little 
to  do  with  the  draught;  the  height 
has  a  slight  influence,  but  bear  in 
mind  constantly  that  the  great  mov- 
ing power  in  all  flues  is  the  variation 
of  temperature. 

Now,  let  us  make  a  practical  appli- 
cation of  this  principle. 

Wait  a  moment:  just  let  us  lay 
this  one  aside,  but  not  forget  it,  as 
we  shall  want  to  refer  to  it  in  a  few 
moments,  and  try  another  experiment  which  has  some  bearing  upon 
the  subject. 

I  have  here  a  tube  just  one  foot  square  and  two  feet  long,  and  one 
foot  from  the  bottom  there  is  what  we  will  suppose  to  be  an  air- 
tight piston  that  can  be  moved  without  fric- 
tion. Now,  suppose  we  heat  that  air  490° 
(for  the  sake  of  easy  remembering,  say  500°); 
this  would  just  double  its  volume — it  would 
then  be  two  cubic  feet  in  size  instead  of  one. 
Now,  suppose  that,  instead  of  letting  this 
air  expand,  we  should  put  a  weight  on  it,  so 
as  to  keep  it  in  its  place,  how  much  do  you 
think  we  should  have  to  place  on?  Two 
thousand  one  hundred  and  sixty  pounds,  or 
about  one  ton.  Now,  what  do  we  find  these 
2160  pounds  to  represent  ?  It  is  the  weight  of 
a  column  of  atmosphere  with  a  base  of  one  foot  square,  or  fifteen 


Fig.  14. 


39 

pounds  multiplied  by  144  square  inches — it  is  the  weight  that  wouH 
rest  upon  the  piston  if  all  the  air  was  ta'ken  out  from  under  it. 
Therefore,  if  you  add  about  500°  of  heat  to  a  cubic  foot  of  air,  it 
makes  it  two  cubic  feet  of  air ;  or,  if  you  attempt  to  keep  it  from 
expanding,  you  must  put  a  ton  weight  upon  it. 

Mark  one  thing,  however,  if  it  takes  ten  ounces  of  coal  to  heat  that 
air  to  490°,  which  we  do  by  piling  our  ton  weight  upon  it,  it  will 
take  fourteen  ounces  of  coal  if  we  allow  it  to  expand  to  two  feet. 

In  the  former  case,  where  the  air  remains  stationary,  it  had  done 
no  work.  It  was  ready  to  go  to  work,  but  it  had  not  commenced. 
But  in  the  case  of  its  expansion,  it  had  done  a  great  work.  What 
was  it?  Why  it  had  lifted  that  ton  of  atmospheric  air  one  foot  in 
height,  and  that  work  was  what  used  up  the  difference  between  ten 
parts  and  fourteen  parts  of  coal  (I  don't  trouble  you  with  fractions). 

You  see,  therefore,  to  make  the  air  quit  the  earth  and  ascend  into 
the  upper  regions,  requires  a  positive  power,  the  same  as  it  does  to 
drive  some  poor  simple  people  away  from  the  fire  on  a  cold  day. 

We  often  say  that,  by  heating  air,  we  give  it  power  to  ascend  ; 
instead  of  which  heating  it  destroys  its  power  to  maintain  its  position. 
It  weakens — enervates  it — so  that  its  neighbors  easily  drive  it  out 
and  take  its  place. 

One  cubic  foot  of  air,  diluted  to  two  fe«t,  would  be  driven  about 
two  miles  and  a  half  high  before  it  found  any  body  as  weak  as  itself, 
for  every  350  feet  in  height,  in  round  numbers,  the  pressure  dimin- 
ishes by  an  amount  equal  to  one  degree,  or  forced  under  water 
thirty-four  feet  reduces  it  to  one-half  its  bulk. 

Now,  let  us  go  back  and  finish  our  syphon,  or  flue  experiment. 

Here  we  have  our  little  glass  house  again.  We  will  take  the  roof 
off  and  put  a  pretty  large  'family  in  it — I  mean  large  in  numbers,  if 
not  in  size.  You  may  call  it  a  school,  or  public  meeting,  or  church, 
or  whatever  you  please.  Suppose,  for  illustration,  we  call  it  a 
church,  and  we  will  call  this  larger  light  in  this  end  the  minister 
speaking  to  the  congregation.  You  see,  the  lights  are  a  good  deal 
agitated,  and  flare  around  a  good  deal. 

There  is  a  rush  of  air  down  at  this  end,  and,  as  it  becomes  heated, 
it  rises  at  the  other.  Let  us  cover  about  one-half  of  this  up.  Now 
see  what  a  rush  of  air  there  is  down  these  flues,  instead  of  up  them, 
as  there  ought  to  be.  Here,  you  see,  the  main  body  of  the  building, 
though  much  shorter  than  the  flues,  forms  the  heated  leg  of  the 
syphon ;  and  you  may  thus  recognize  why  many  of  the  ventilating 


40 

flues,  put  in  the  cold  outside  walls  of  many  of  our  large  buildings, 
persist  in  working  the  wrong  way,  and  cold  air  blows  down  there, 
instead  of  the  foul  air  going  up. 

But  there  seems  to  be  too  much  draught.  Let  us  put  the  roof  on. 
Ah,  that  is  better ;  but,  then,  what  a  draught  there  is  down  this 
chimney-flue.  Call  the  sexton,  and  have  that  stopped  up  quickly,  or 
those  sitting  near  there  will  soon  catch  their  death  of  cold,  and  will 
never  come  here  again. 

You  see,  however,  they  shine  very  brightly,  notwithstanding  all 
the  draught,  but  there,  now,  it  is  all  closed  up  as  snugly  as  the  most 
fashionable  church  in  town.  See  how  quiet  and  peacefully  they  burn 
now. 

Ah,  there  is  one  just  gone  to  sleep.  You  must  excuse  him,  he 
probably  was  up  most  of  the  night  with  a  sick  child.  And  there 
goes  another.  I  think  he  must  have  been  very  busy  for  the  last 
week  settling  up  his  last  year's  accounts.  Just  see,  they  are  going 
to  sleep  so  fast,  I  don't  think  we  can  pretend  to  give  excuses  for 
them  all. 

And,  now,  is  not  that  a  brilliant  congregation  to  be  preaching  to? 
Everyone  dead  asleep  excepting  the  preacher  himself,  and  I  suspect 
he  feels  stupid  enough  to  go  to  sleep,  but  it  would  not  look  well; 
and  he  has  to  tax  his  energies  so  severely  he  will  hardly  get  over  it, 
so  as  to  be  good  for  anything  for  the  balance  of  the  week. 

You  may  think  this  an  exaggerated  representation  of  the  real 
facts.  Do  not  deceive  yourselves.  A  few  months  since  I  was 
requested  by  one  of  the  congregation  to  visit  a  building  within  a  few 
minutes'  walk  of  this  place,  and  see  if  there  was  not  some  defect  in 
the  ventilation.  The  gentleman  stated  to  me  that  he  sometimes 
attended  the  class-meeting,  and  would  be  glad  to  go  oftener,  but  it 
was  held  in  the  basement  story,  and  it  was  quite  impossible  for  him 
to  keep  awake,  as  he  had  to  get  up  and  go  out  two  or  three  times 
during  the  evening,  to  get  a  little  fresh  air,  or  he  could  not  keep  awake. 

I  examined  it.  The  ceilings  were  low — only  nine  or  ten  feet; — 
then  there  were  two  old  leaky  portable  furnaces,  which  were  used  as 
occasion  required  for  heating  the  large  room  above,  or  the  basement 
room  when  the  class-meeting  was  held. 

The  only  ventilation  they  had  was  to  let  off  the  surplus  heat  (if 
they  had  any,  which  was  seldom)  into  the  room  above. 

Now  for  fresh  air.  By  a  very  careful  and  minute  examination,  I 
discovered  a  little  pipe  (I  think  it  was  about  six  inches  in  diameter) 


41 

to  each  stove  (both  of  which  would  not  be  over  half  as  large  as  what  I 
have  to  supply  my  own  bedroom),  for  the  supply  of  the  fresh  air  for 
that  whole  congregation.  Fresh  air,  did  I  say  ?  Well,  let  us  see  where 
this  fresh  air  comes  from.  The  janitor,  after  taking  us  down  and 
showing  where  he  kept  the  ashes,  wood,  old  benches,  and  all  sorts  of 
rubbish,  was  about  going  up,  but  said  I,  "Where  is  the  part  where 
you  get  the  fresh  air  to  the  furnaces?"  "Oh,"  he  said,  "  he  could 
not  get  to  that,  it  was  such  a  rough  place,  and  there  was  a  sewer  or 
gutter  (from  the  adjoining  graveyard  I  suppose)  running  right  across 
it."  And  from  that  place,  too  rough  to  be  got  at,  with  an  open  sewer 
running  through,  and  too  foul  to  go  into,  was  where  they  got  the 
fresh  air  (!)  from  for  the  whole  of  that  congregation  to  breathe. 

And  do  you  suppose  this  is  an  exception  ?  Let  me  tell  you.  During 
the  first  year  of  the  late  war  I  was  called  upon  by  the  Sanitary 
Commission  to  examine  the  hospitals  in  Washington  City  with  refer- 
ence to  their  ventilation.  A  large  number  of  the  churches  in  that 
city  were  used  for  hospital  purposes,  and  many  of  them  were  heated 
by  hot-air  furnaces,  and  in  not  one  single  instance  had  they  fresh  air 
boxes  to  them,  neither  had  they  any  means  for  carrying  off  the  foul 
air.  The  furnaces  were  generally  placed  in  a  hole  excavated  under 
the  main  part  of  the  building,  and  all  the  ground  around  them  left 
exposed,  and  the  air  was  sucked  in  from  the  fermenting,  decaying 
vegetable  mould  under  the  building.  And  this  place  around  the 
furnace  was  the  place  where  all  the  filth  and  old  rubbish  was  thrown 
to  get  it  out  of  the  way,  and  it  was  thoroughly  out  6f  the  way  too,  for 
the  surgeon  in  charge  or  any  inspector  never  got  there  to  see  it.  In 
some  cases  I  found  this  space  around  the  furnace  used  as  the  dead 
house ! 

Did  I  say  there  was  no  attempt  in  any  of  those  buildings  for  syste- 
matic ventilation  ?  I  ought  to  have  made  one  exception. 

I  called  one  morning  about  ten  o'clock  at  one  of  the  finest  new 
churches,  which  was  then  being  occupied  as  a  hospital,  and  asked 
for  the  surgeon  in  charge.  He  had  not  arrived.  (They  did  not  often 
venture  in  before  eleven  o'clock,  the  wards  became  so  foul  during  the 
night  it  took  till  that  time,  with  the  windows  up,  to  get  them  fit  for 
the  surgeon  in  charge  to  venture  in.)  I  inquired  of  the  wardraaster 
how  the  building  was  ventilated.  "Oh,  very  well — very  well,  indeed 
— they  had  good  ventilation,"  pointing  up  to  a  large,  splendid  venti- 
lator in  the  ceiling.  "Do  you  keep  that  always  open?"  I  asked. 
"  Oh,  certainly,"  he  replied.  But  I  always  have  a  great  suspicion 


42 

of  those  ceiling  ventilators,  as  they  are  generally  shut.  So  I  walked 
around  the  ward,  and  when  under  it  asked  him  again  if  he  thought 
that  was  open.  A  smile  came  over  his  face  as  he  discovered,  for  the 
first  time,  it  was  a  handsome  fresco  painting  on  the  solid  wall.  And 
this  was  the  only  practical  systematic  attempt  at  any  ventilation  in 
any  of  the  church  buildings  used  as  hospitals  in  all  Washington. 

I  have  not  been  in  any  of  the  public  schools  in  this  city  for  many 
years,  but  a  gentleman  told  me  the  other  day  that  he  called  at  one  of 
the  fashionable  schools  up  town  to  get  his  son  and  take  him  home 
under  his  umbrella,  as  it  had  commenced  raining  since  morning,  and 
as  he  opened  the  school  room  door  he  was  perfectly  shocked,  as  he 
staggered  back  from  the  gust  of  horrible  foul  air  that  came  rushing 
out  of  that  room. 

I  have  examined  most  of  the  public  schools  in  New  York  since  I 
have  those  of  Philadelphia. 

They  have  a  way  of  their  own  of  doing  public  business  over  there. 
There  has  been  a  good  deal  said  about  ventilating  public  schools  of 
late  years,  and  as  it  was  such  a  scientific  and  fashionable  matter  they 
must  have  their  schools  ventilated  of  course. 

I  was  very  unfortunate  in  my  intercourse  with  the  Directors  of 
the  Public  Schools.  I  did  not  happen  to  meet  with  many  of  those 
high  toned,  liberal,  scientific  gentlemen  that  are  on  many  of  the 
committees,  of  course. 

Those  beautiful  and  ornamental  gratings  called  registers  are 
accepted  as  the  external  proof  of  good  ventilation,  suggesting  as  they 
do  the  flow  of  an  abundance  of  pure  fresh  air.  So  registers  were 
bought  freely  and  put  in  all  the  rooms,  top  and  bottom,  with  splendid 
red  and  green  and  blue  tassels,  altogether  making  a  handsome  show 
and  doing  the  very  able  and  scientific  gentlemen  on  the  School 
Boards  great  credit  for  their  enterprise  and  great  care  for  the  welfare 
and  interest  of  the  pupils  under  their  charge. 

Now,  let  us  examine  the  operation  of  these  registers.  Holding  a 
handkerchief  in  front  of  them,  there  it  remained  perfectly  motionless. 
It  neither  blew  hot  nor  cold — it  was  perfectly  lukewarm,  motionless. 
Go  to  another — the  same.  And  to  another — the  same.  Well  that  is 
singular.  Let  us  go  on  the  roof  and  see  what  can  be  the  matter. 
A  careful  search  fails  to  discover  any  flues  at  all,  but  a  mechanical 
examination  shows  that  the  coping-stone  has  been  put  on  them, 
making  all  the  flues  as  thoroughly  air-tight  as  the  solid  wall — more 
perfectly  capped  than  that  chimney.  There  had  been  no  attention 


43 

paid  to  having  the  holes  for  the  ventilating  flues  cut  through  the 
coping-stone. 

Yes,  I  believe  that  to-day  a  large  proportion  of  all  those  flues  with 
the  elegant  ventilating  registers  at  the  top  and  bottom  of  the  room, 
are  capped  and  made  as  thoroughly  air-tight  as  the  solid  wall,  and 
are  as  perfect  shams  and  as  useless  as  the  elegant  frescoed  ventilator 
on  the  solid  wall  of  the  church  hospital  in  Washington. 

I  do  not  believe  that  Philadelphians  have  gone  quite  thus  far  in 
satisfying  the  public  demand  for  ventilation  in  the  public  schools. 
They  may  not  have  done  any  more,  but  I  believe  they  have  not 
pretended  to  do  quite  as  much. 

Excuse  me  a  few  minutes;  I  must  illustrate  another  very  great 
deficiency.  The  simple  illustration  I  will  give  you  represents  almost 
the  universal  condition  of  our  hot-air  furnaces. 

Much  complaint  was  made  of  the  uncomfortable  feeling  in  one  of 
the  large  public  schools,  where  they  had  some  1200  or  1500  scholars. 
I  was  called  to  examine  it.  I  asked,  as  is  my  usual  habit,  if  they 
evaporated  plenty  of  water.  "Oh,  yes;  they  had  given  the  janitor 
full  directions  about  keeping  the  evaporating  pans  always  full."  I 
found  the  evaporating  pans  full,  sure  enough,  rather  to  my  surprise, 
but  what  do  you  think  they  were  filled  with?  Several  old  brooms, 
half  charred,  and  some  old  water  buckets  all  fallen  to  pieces,  and 
other  rubbish  thrown  in  there  out  of  the  way. 

And  now  those  of  you  who  have  been  trusting  to  your  servants  to 
"keep  water  in  -your  furnaces,  if  you  will  take  a  candle  when  you  go 
home  and  go  down  and  examine  your  own  furnaces,  you  will  most 
likely  find  them  dry,  and  if  you  go  to  the  public  schools  in  the  morning 
you  will  see  that  they  too  are  not  an  exception. 

I  wish  I  had  time  to  explain  the  dreadful  effect  of  this  want  of 
moisture  in  all  our  artificially  heated  rooms.  The  air  in  winter  is 
very  dry,  the  moisture  is  squeezed  out  as  the  water  is  squeezed  out 
of  this  sponge.  But  as  you  heat  it  you  enlarge  its  volume  again, 
and  it  sucks  up  the  moisture  just  as  this  sponge  does,  and  if  you  do 
not  supply  this  moisture  in  other  ways  it  will  suck  the  natural 
moisture  from  your  skin  and  your  lungs,  creating  that  dry,  parched, 
feverish  condition  so  noticeable  in  our  furnace  and  other  stove-heated 
rooms.  Few  persons  realize  the  great  amount  of  water  necessary  to 
be  evaporated  to  produce  the  natural  condition  of  moisture  corres- 
ponding with  the  increased  temperature  given  the  air  in  many  of  our 
rooms  in  winter. 


44 

I  have  copied  a  table  expressing  in  grains  troy  the  moisture  con- 
tained in  one  cubic  foot  of  air  when  saturated: 

Degrees  Grains  of  vapor 

Fahrenheit.  in  cubic  foot. 

10 -8 


30 2- 

40 29 

50 4- 

60 6- 

70 8- 

so lo- 
go  15- 

100 19. 

Thus  you  see,  taking  the  air  at  10°  and  heating  up  to  70°,  the 
ordinary  temperature  of  our  rooms,  requires  about  nine  times  the 
moistue  contained  in  the  original  external  atmosphere,  and  if  heated 
to  100°,  as  most  of  our  hot-air  furnaces  heat  the  air,  it  would  require 
about  twenty-three  times  the  amount  in  the  external  atmosphere. 

This  is  a  very  interesting  and  important  subject,  but  I  am  sorry  I 
have  not  time  for  further  explanation. 

I  see  some  kind  friend  has  been  around  and  opened  the  doors  of 
our  meeting-house  and  awakened  the  sleepers.  And  now  you  see  the 
lights  shine,  and  the  cheeks  glow  as  brightly  as  would  those  of  our 
young  ladies  could  they  be  persuaded  to  go  skating,  or  take  a  five 
mile  walk  every  day,  rain  or  shine,  and  sleep  with  the  windows  open, 
and  never  ride  in  any  of  our  cars,  or  go  to  parties  or  any  other  public 
^nthcrings  unless  the  buildings  where  they  are  held  are  well  venti- 
lated. 

But  these  dreadful  drafts !  People  will  not  bear  them.  Let  us 
see  if  we  can  accommodate  them.  Put  on  the  roof,  and  here  comes 
this  dreadful  current  again  down  the  ventilating  flue.  Well,  venti- 
lating flues  have  the  name  of  being  great  humbugs.  Let  us  shut 
them  up.  There  are  your  poor  consumptive  patients — there  they  go, 
you  see.  One-half  dead  already,  and  the  rest  will  soon  follow  if  we 
cannot  rescue  them.  Let  us  open  the  flue  again.  See  how  they 
brighten  up  as  the  fresh  air  comes  in.  There  is  no  use  of  disputing 
about  it,  you  must  have  a  current  of  fresh  air  coming  into  the  house 
or  you  will  surely  die. 

Now  let  us  change  the  programme.  Let  us  build  a  fire  in  this 
fire-place  in  the  lower  story — that  burns  up  brightly.  Where  does  it 
get  fresh  air  from  now?  There  can  be  no  current  down  the  chimney. 


45 

Let  us  search  it  out  with  this  smoking  taper.  Ah,  here  it  is  coming 
down  through  the  ventilator  from  the  very  top  of  the  house.  We  will 
soon  stop  that  by  this  cap.  But  see,  it  still  burns  as  brightly  as 
ever.  Let  us  try  again.  Ah,  do  you  see  the  smoke  rushing  down 
the  second  story  chimney  and  across  to  the  stairway,  and  down  the 
stairs,  and  across  the  room  again  to  this  fire  ? 

There  is  a  valuable  hint.  Have  you  not  noticed  frequently  gas  in 
the  room  from  the  fire-place  or  stove,  and  especially  at  night?  And 
do  you  see  how  easily  it  would  be  to  account  for  it  if  the  house  were 
shut  up  tight  at  night,  with  a  large  fire  in  the  kitchen  or  furnace  in 
the  cellar,  and  but  a  small  fire  in  the  second  story?  Don't  you  see 
how  the  whole  products  of  combustion,  all  the  poisonous  gases,  may 
be  drawn  out  into  the  room  ?  You  often  notice  accounts  of  whole 
families  being  smothered  to  death  in  one  night,  but  many  seem  to 
think  if  they  are  not  smothered  to  death  the  first  night,  that  it  is  not 
so  very  dangerous  after  all,  and  not  knowing  how  to  remedy  it  easily 
go  on  from  day  to  day  and  sometimes  escape  the  whole  winter  with  a 
little  of  their  lives  left. 

Now,  let  us  put  out  the  fire  in  the  first  story  and  make  one  in  the 
second. 

You  must  remember  that  this  is  not  a  fashionable  .double  ceiled 
and  plastered  air-tight  house.  It  is  much  more  open,  in  proportion 
to  its  size,  than  any  ordinary  house.  And  now,  as  this  lower  flue  has 
been  so  highly  heated,  it  may  take  some  time  for  the  fire  in  the 
second  story  fire-place  to  become  heated  sufficiently  in  excess  to 
cause  the  air  to  draw  down  the  longest  flue  to  the  bottom  of  the 
house  and  up  the  stairs  to  the  second  story  fire-place,  but  it  will  soon 
do  it. 

I  wish  you  to  notice  one  -thing  here  particularly,  and  each  one 
apply  it  to  your  own  particular  case.  You  know  the  lower  part  of 
the  house  is  closed  up  tight  to  keep  out  the  robbers,  and  if  great  care 
is  not  taken  to  give  an  abundant  supply  of  fresh  air  to  your  chambers 
otherwise,  it  will  be  drawn  up  through  the  hall  out  of  your  kitchen 
and  cellar,  and  as  the  cook  has  left  the  range  lid  off  and  shut  the 
dampers,  you  will  have  a  suffocating  smell  of  gas  all  over  the  house. 
But  the  worst  danger  of  all  is  the  air  that  may  be  drawn  in  from  an 
untrapped  sewer  or  cesspool.  This  is  a  very  common  but  great 
source  of  ill-health. 

Sanitarians  have  given  much  attention  to  this  subject  lately,  and 
have  been  astonished  at  the  magnitude  of  the  evil.  I  have  long  main- 


46 

tained  that  a  family  might  go  to  the  highest  and  most  healthy  location 
in  the  world,  and  by  a  little  carelessness  might  accumulate  sufficient 
filth  around  them,  and  by  closing  up  the  house  at  night  and  allowing 
the  foul  gases  from  untrapped  sewers  and  cesspools  to  enter  through 
the  halls  to  their  sleeping  rooms,  to  thus  make  what  would  other- 
wise be  a  healthy  place  a  very  unhealthy  one. 

As  a  case  in  point,  I  would  refer  to  a  very  interesting  report  of 
Doctors  Palmer,  Ford,  and  Earle,  giving  an  account  of  their.investiga- 
tions  of  the  causes  of  a  severe  epidemic  that  occurred  in  the  summer 
of  1864  in  a  young  ladies'  seminary  in  Massachusetts.  "  The 
Maplewood  Institute"  is  situated  in  Pittsfieltl,  one  of  the  most  beau- 
tiful of  those  charming  New  England  villages,  which,  to  external 
appearances,  are  the  very  emblem  of  all  that  is  pure  and  healthy. 
Yet  even  in  this  lovely  place,  from  an  ignorant  or  careless  arrange- 
ment of  the  drains  and  cess-pools,  much  of  the  foul  gas  generated 
there  found  its  way  into  the  building,*  making  sixty-six  out  of  seventy- 
four  young  ladies  sick,  fifty-seven  of  whom  had  the  typhoid  fever  and 
thirteen  died.  Many  similar  cases  are  frequently  occurring,  some 
few  of  which,  like  this,  are  carefully  investigated,  and  the  causes 
removed.  Many  more,  however,  go  unnoticed,  and  are  accepted  as 
special  dispensations  of  Providence,  when  it  is  all  due  to  our  own 
negligence. 

I  want  to  show  you  an  arrangement  that  ought  to  be  in  every 
house.  We  have  seen  the  power  of  a  fire  to  create  a  draft,  and  if 
you  will  think  a  little  you  will  notice  that  the  kitchen  fire  is  the  most 
considerable  and  most  permanent  power  in  ordinary  dwellings,  and 
this  ought  to  be  made  use  of  to  ventilate  the  kitchen,  water-closet 
and  bath-room  in  every  house.  But  you  must  not  make  an  opening 
directly  into  the  kitchen  flue; if  you  do  you  will  interfere  with  the 
draft  of  the  kitchen  fire,  and  if  you  interfere  with  the  kitchen  fire 
you  will  soon  wish  yourself  at  anything  but  keeping  house. 

But  we  can  easily  get  over  that  trouble.  We  will  use  this  square 
glass  box  again  to  represent  a  flue.  I  don't  mean  this  to  represent  the 
size — it  ought  to  be  twice  that  size.  In  the  centre  we  will  put  a  cold 
pipe,  to  show  you  that  a  pipe  without  any  heat  in  it  would  only  cause 
the  foul  air  to  tumble  down  into  the  room.  Thus  you  see  the  smoke 
descending.  We  will  substitute  a  pipe  with  a  gas  light  to  heat  it. 


*  In  addition  to  which  there  appeared  to  be  a  deficiency  in  the  arrangements  for 
ventilation. 


47 


Fig.  15. 


Now  you  see  what  a  rapid  current  there  is  out  of  this  large  flue.  See 
what  a  splendid  arrangement  this  is  for  ventilating,  and  it  may  be 
extended  so  as  to  ventilate  the  whole  house.  It  is  not  necessary  that 
the  room  to  be  ventilated  should 
be  adjoining,  but  a  pipe  can  be 
carried  between  the  floors  50  or 
100  feet. 

I  had  an  opportunity,  during 
the  late  war,  of  thoroughly  test- 
ing this  system  of  ventilation  in 
the  government  hospitals. 

Let  me  say  here  that  a  very 
common  mistake  in  making  ven- 
tilating flues  is,  that  they  are  en- 
tirely too  small  to  be  of  any  value. 
One  of  these  little  Philadelphia 
flues,  four  by  nine  inches,  made 
with  rough  bricks,  and  nearly  or 
entirely  choked  up  with  mortar, 
as  many  of  them  are  frequently 
found,  is  of  no  account.  They 
are  simply  a  deception,  and  a  perfect  provocation  to  a  sensible  man. 

I  commenced  by  making  some  in  Washington,  for  single  wards, 
thirty  inches  square,  but  in  St.  Louis,  and  Louisville,  and  Nashville, 
where  buildings  four  or  five  stories  high  were  used  for  hospitals,  I 
made  them  much  larger,  some  three  feet  square  and  some  four  feet 
by  six  feet.  Some  buildings,  where  the  ventilation  was  so  bad  and 
the  water-closets  were  so  offensive  that  the  government  had  to  abandon 
them,  I  had  ventilated  by'  these  immense  shafts,  heated  by  the 
kitchen  and  laundry  fires,  which  proved  thoroughly  efficient  and 
entirely  satisfactory.  . 

I  had  hoped  to  have  time  to  discuss  the  subject  of  heating  more 
fully  in  connection  with  ventilation,  but  cannot;  but  I  will  state,  in  the 
simplest  manner,  a  few  of  the  leading  points  first. 

You  must  have  fresh  air  all  the  time.  In  summer  you  can  get  it 
by  opening  the  doors  and  windows.  In  winter  it  must  be  warmed 
before  entering  the  room.  It  must  not  enter  the  room  cold  and  flow 
across  the  floor  to  the  other  side  before  it  reaches  the  heating  appara- 
tus. You  can  bear  a  large  amount  of  fresh  air  if  it  strikes  you  in 
the  face  and  evenly  over  the  whole  body,  but  never  let  a  jet  of  cold 
air  blow  upon  any  small  portion  of  your  body. 


48 

To  avoid  these  local  currents  sucking  in  at  cracks,  you  must  make 
provision  for  the  introduction  of  an  amount  of  air  larger  than  the 
sum  of  all  these  cracks,  and  yonr  exhaust  flue  besides.  This  air  must 
be  partially  warmed  before  entering.  If  this  is  done  by  a  hot-air 
furnace,  it  must  have  a  large  fresh  air  box,  which  should  be  from 
eighteen  inches  to  two  feet  for  a  large  house.  It  should  have  a  large 
evaporating  vessel,  with  a  ball-cock  to  supply  it.  You  cannot  get 
the  servants  to  attend  to  it,  and  you  must  never  allow  the  air  from 
your  cellar  to  enter  your  furnace  to  be  driven  up  stairs.  Never 
allow  the  furnace  to  get  red-hot. 

A  hot  water  furnace  disturbs  the  natural  conditions  of  the  air  the 
least,  and,  on  that  account,  is  a  very  healthy  means  of  artificially 
heating  air.  But  they  are  necessarily  expensive,  and  so  few  persons 
really  appreciate  the  value  of  pure  air,  that  but  few  will  go  to  the 
expense  of  introducing  them.  It  is  a  mistake  to  suppose  that  they 
do  not  dry  the  air,  so  to  speak.  You  cannot  elevate  the  temperature 
without  increasing  the  capacity  for  moisture.  A  hot  water  furnace, 
therefore,  requires  the  artificial  evaporation  of  water  to  give  the 
warmed  air  its  true  hygrometric  condition. 

Heating  the  air  by  steam  is  the  next  most  healthy  means;  as  the 
surfaces  used  are  heated  a  little  hotter,  less  of  it  answers  the  same 
purpose.  The  first  cost  is  therefore  less.  It  is  the  most  rapid  and 
convenient  means  of  conveying  heat  to  any  distant  point  of  anything 
now  in  use.  Under  the  pressure  of  an  ordinary  boiler  it  will  travel 
seven  miles  in  one  minute.  The  time  I  hope  is  not  far  distant  when 
the  subject  of  heating  and  ventilation  will  receive  an  amount  of 
attention  due  to  its  importance.  I  believe  then  we  shall  have  steam 
pipes  laid  through  our  streets,  the  same  as  gas  and  water  now  are. 
The  present  system  of  each  man  keeping  up  separate  fires  all  over 
his  house  is  as  crude,  and  extravagant,  and  unnecessary  as  it  would 
be  for  every  man  to  make  his  own  gas  or  have  his  own  well  for 
water. 

Where  a  steam  furnace  is  used,  two-thirds  of  the  heating  surface 
should  be  put  below  the  floor  and  fresh  air  brought  into  it,  and  from 
there  conducted  to  the  rooms  through  large  pipes.  This  warmed  air 
should  be  let  into  the  room  at  the  floor,  and  an  opening  into  an 
exhaust  flue,  two-thirds  the  size  of  the  inlet,  should  be  provided  at 
the  floor  for  the  escape  of  the  foul  air.  The  remaining  one-third  of 
the  heating  surface  should  be  exposed  in  the  halls  and  some  in  the 
other  parts  of  the  house,  to  heat  by  direct  radiation,  but  under  no 


49 

circumstances  should  a  room  or  office  be  occupied  heated  exclusively 
by  direct  radiation  from  exposed  steam  pipes.  It  is  one  of  the  worst, 
most  unhealthy,  killing  systems  in  existence. 

Steam  furnaces  require  the  evaporation  of  an  additional  amount 
of  moisture  as  well  as  any  other  system  of  heating.  According  to 
Dr.  Wetheral's  investigation,  it  would  require  the  evaporation  on 
some  days  of  nearly  forty  pounds  of  water  every  minute  in  the  Senate 
Chamber  to  maintain  the  proper  hygrometric  condition.  Probably 
one  of  the  very  best  arrangements  is  to  have  a  good  steam  furnace, 
with  a  large  fresh  air  box  letting  in  an  abundance  of  air  moderately 
warmed,  and  overflowing  the  house  with  this,  and  some  direct  radia- 
tion in  the  halls,  and  a  good,  bright,  cheerful  open  fire  in  the  family 
sitting-room. 

But  if  you  cannot  have  a  steam  or  hot  water  furnace,  you  can 
make  a  room  very  comfortable  indeed  with  a  stove,  if  you  will  but 
introduce  all  the  fresh  air  required  for  the  room  directly  against  or 
on  top  of  the  stove.  No  stove  ought  to  be  put  up  without  having  a 
supply  of  fresh  air  from  the  outside,  and  a  large  evaporating  vessel, 
kept  constantly  filled  with  water,  with  an  opening  in  the  heated  flue 
near  the  floor  for  the  escape  of  the  foul  air. 

In  conclusion,  allow  me  to  urge  upon  you  to  examine  your  furnace 
this  evening  or  to-morrow  morning,  and  if  there  is  no  fresh  air  box 
communicating  with  the  external  atmosphere,  go  to  the  nearest  car- 
penter's shop  before  going  to  your  business,  and  get  him  to  come  at 
the  earliest  possible  moment  and  put  in  a  good  large  one,  and  if  he 
asks  you  where  you  want  the  damper  in  the  cold  air  box,  tell  him 
you  don't  want  any. 

Dampers  in  cold  air  boxes  are  handy  things  to  have  in  the  house, 
when  used  properly,  but,  like1  fire-arms,  are  very  dangerous  if  you  do 
not  understand  them.  Yes,  dampers  in  cold  air  boxes  and  other 
contrivances  for  keeping  the  fresh  air  out  of  houses,  have  killed  more 
persons  than  all  the  fire-arms  ever  made  in  this  country  or  any  other. 

If  you  have  no  evaporating  vessel  in  the  furnace,  stop  at  your 
furnace  man's,  and  tell  him  to  put  in  two  good  large  evaporating 
vessels  in  such  a  position  that  they  will  evaporate  two  or  three 
buckets  of  water  a  day  in  cold  weather. 

And  if  you  have  a  stove  at  your  office,  stop  on  your  way  down  and 
buy  a  good  large  earthen  pan  to  set  on  the  top  of  the  stove,  and 
keep  it  always  full  of  water.  Make  a  pipe  for  the  inlet  of  fresh  air 
to  every  stove  over  which  you  have  any  control,  and  never  remain 


50 

in  a  room  one  day  without  a  good  opening  at  the  floor  for  the  escap? 
of  foul  air. 

And  from  my  own  experience,  and  that  of  many  others  whom  1 
know  to  have  given  much  attention  to  this  subject,  I  can  assure  you, 
with  the  fullest  confidence,  that  you  will  be  most  amply  rewarded  for 
your  care  in  this  respect  by  increased  health,  strength  and  happiness, 
and  by  the  reasonable  prospect  of  a  long  life. 


VENTILATION. 


THE  GRAND  PRIZE  AWARDED  AT  THE  PARIS  EXHIBITION. 


ADDED  to  the  many  other  gratifying  signs  of  a  rapidly  increasing 
interest  in  the  all-important  subject  of  the  proper  supply  of  pure  air 
to  our  houses,  is  the  awarding  of  the  grand  prize  of  the  Paris  Exhibi- 
tion to  Dr.  Evans, for  an  American  sanitary  collection. 

The  Sanitary  Commission,  during  our  late  war,  acted  upon  the 
principle  since  expressed  by  the  report  of  the  Board  of  Health  of 
New  York.  They  say  :  "  And  viewing  only  the  causes  of  prevent- 
able diseases  and  their  fatal  results,  we  unhesitatingly  state  that  the 
very  first  sanitary  want  in  New  York  and  Brooklyn  is  VENTILATION 
— ventilation  supplied  in  all  existing  tenant-houses,  work-rooms, 
school-rooms  and  places  of  assemblage — and  in  all  that  shall  here- 
after be  constructed." 

The  early  recognition  during  the  late  war,  both  by  the  Sanitary 
Commission  and  the  government  officials,  of  the  important  fact  that 
many  more  men  are  killed  by  breathing  foul  air  than  are  killed  by 
the  enemies'  bullets,  led  them  to  use  very  active  exertions  to  secure 
good  ventilation  in  hospitals  and  camps,  and  to  teach  the  men  them- 
selves the  value  thereof.  The  result  has  been  highly  satisfactory. 
The  fact  that  we  must  make  some  positive  provision  for  a  constant 
supply  of  fresh  air  to  every  occupied  room,  and  not  rely  on  accidental 
cracks  and  openings,  is  now  very  generally  felt.  The  simple,  prac- 
tical and  efficient  means  used  by  the  government  has  done  much  to- 
wards creating  this  wholesome  public  opinion. 

The  annexed  plan  (excepting  a  stove  and  twelve  beds,  omitted  from 
centre  of  plan,  indicated  by  the  space)  is  a  copy  of  one  I  furnished 
the  Committee;  and  which  was  faithfully  executed  in  preparing  one 
of  the  models  of  hospitals,  the  arrangements  of  which  have  been  so 
highly  appreciated,  and  has  shared  one  of  the  grand  prizes  at  the 
Paris  Exhibition. 

It  is  a  representative  plan,  showing  the  general  arrangements  of 
wards  in  a  large  number  of  the  hospitals. 


52 


Fig.  1. 


c=]    cm 

1 


EZH 

CZJ 


J  _______  L. 


i i. 


fUr 


czn     cm 


FT// r 
'0/w 


The  special  arrange- 
ments of  flues,  v,  for  win- 
ter ventilation,  and  the  in- 
troduction of  the  fresh  air 
around  the  stove,  were  not 
introduced  into  the  hospi- 
tals in  Philadelphia,  built 
at  the  commencement  of 
the  war.  And  the  subse- 
quent orders  of  the  Sur- 
geon General  and  Quarter 
Master  General  for  the 
introduction  thereof  were 
protested  against  by  the 
Surgeons  of  Philadelphia, 
owing  probably  partially 
to  their  proverbial  ob- 
jection to  changes  of  any 
kind,  and  partially  to 
that  dread  of  "ventila- 
tion" made  but  too  popu- 
lar by  the  many  erroneous 
theories  which  propose  to 
introduce  the  fresh  air 
directly  into  the  room, 
and  at  times,  too,  when  it 
is  even  below  the  freezing 
point,  without  first  warm- 
ing it.  These  arrange- 
ments, shown  in  the  ac- 
companying plan  and  sec- 
tion, were  thoroughly  test- 
ed, however,  in  many  of 
the  hospitals  subsequently 
built  in  many  of  the  West- 
ern cities. 

The  plan  of  ridge  venti- 
lation, shown  in  the  accom- 
panying section,  I  applied 
first  in  St.  Louis,  in  the 
summer  of  1863.  It  is 


53 

the  principle  of  the  Emerson  ventilator  applied  to  ridge  ventilation. 
Much  trouble  had  been  experienced  with  other  forms  on  account  of 
their  allowing  the  storms  to  beat  inland  the  difficulty  of  opening  and 
closing  them  with  the  various  changes  of  wind;  this  form  fully  remedies 
those  objections,  and  can  be  left  open  without  inconvenience  at  all  times 
while  snowing  or  raining.  It  uses  the  force  of  the  wind, whenever  there 
is  a  current  passing  over  the  top  of  the  building,for  sucking  the  air  out 
of  the  ward,  because  the  air  in  passing  across  the  top  of  the  build- 
ing is  deflected  from  the  straight  line  by  the  angle  of  the  roof-board, 
which  creates  a  partial  vacuum  in  the  space  below,  which,  with  the 
friction  of  the  passing  current  with  that  coming  out  of  the  ward, 

Fig.  2. 


makes  an  outward  draught,  varying  in  proportion  to  the  velocity  of  the 
external  current.  This  is  often  very  useful,  especially  in  summer, 
when  there  is  not  sufficient  difference  between  the  external  air  and 
that  in  the  ward  to  create  a  current.  There  is  often  a  considerable 
force  in  the  passing  current  at  the  top  of  the  building  when  there  is 
much  less  below. 

But  of  course  these  openings  had  to  be  closed  in  winter  to  prevent 


54 

all  the  heat  from  escaping.  It  then  became  necessary  in  wards  that 
had  no  fireplaces,  to  make  something  as  substitutes  therefor.  Wooden 
shafts  or  flues  were  made  to  answer  this  purpose. 

I  at  first  made  large  wooden  boxes,  placing  them  in  the  centre  of  the 
wards,  and  allowing  them  to  extend  down  to  within  twelve  or  eighteen 
inches  of  the  floor.  This  was  of  great  advantage,  but  as  the  true  prin- 
ciple of  ventilation  is  to  have  an  opening  for  the  exit  of  the  contami- 
nated air  at  the  feet  of  each  occupant  of  a  room,  or  at  the  head  of 
the  bed  of  each  patient  in  a  hospital,  it  was  soon  observed  that  these 
shafts  were  too  few  and  far  between  to  make  a  very  perfect  arrange- 
ment. 

The  necessity  for  providing  for  the  escape  of  the  foul  air  from  the 
level  of  the  floor  in  winter,  so  as  to  utilize  the  heat,  was,  after  much 
opposition,  finally  established  and  officially  acknowledged  by  the 
government  officers.  Then  arrangements  were  made  for  its  introduc- 
tion into  the  government  hospitals  in  a  more  perfect  manner. 

I  believe  in  no  case,  however,  was  it  so  fully  carried  out  as  to  place 
a  ventilating  flue  between  each  bed,  but  in  some  they  were  arranged, 
as  shown  (marked  v)  in  the  accompanying  plans  between  every  other 
two  beds. 

These  flues  were  carried  together  and  extended  through  the  ridge 
of  the  roof  and  capped  as  an  Emerson  ventilator ;  the  opening  into 
the  large  flue, extending  to  just  below  the  ceiling, was  closed  in  winter 
at  all  times,  excepting  when  the  room  was  too  warm.  This  was  for 
the  exhaust,  but  of  no  less  importance  was  the  supply. 

The  popular  dread  of  ventilation  arises  in  a  great  measure  from 
the  supposition  that  good  ventilation  impjies  a  strong  draught  of 
cold  air  upon  your  back  or  feet  or  some  other  unfortunately  exposed 
place.  Such  an  unfortunate  occurrence  must  be  fully  remedied  in  any 
svstem  of  ventilation  before  it  can  become  popular. 

As  the  simplest  way  of  getting  at  this,  all  the  fresh  air  required 
to  supply  the  partial  vacuum  created  by  the  exhausting  shafts  was 
brought  in  around  the  stoves,  and  partially  warmed  before  entering. 
At  the  first  the  stoves  were  entirely  encased,  and  the  fresh  air  allowed 
to  encircle  them  completely,  but  experience  soon  demonstrated  the 
desirableness  of  having  a  portion  of  the  hot  stove  exposed  for  direct 
radiation,  so  that  the  feeble  and  chilly  ones  might  come  near  to  it 
and  warm  themselves.  There  should  always  be  a  considerable  amount 
of  direct  radiation  in  every  hospital ;  that  from  an  open  fire  is  the 
best,  but  that  from  a  stove  or  steam-pipe  is  very  good. 


55 

Arrangements  were  also  made  for  the  evnporation  of  a  large  amount 
of  water. 

As  the  first  winter  approached  after  the  commencement  of  the  war, 
the  idea  seemed  almost  shocking  to  me  of  putting  the  sick  and  wounded 
men  in  such  open  barracks,  generally  without  plastering,  and  made,  as 
many  of  them  were,  with  rough  boards  and  very  open. 

But  experience  soon  taught  me  the  very  great  superiority  of  these 
light  and  airy  buildings  over  many  of  the  elaborately  finished,  dark, 
air-tight  structures,  such  as  hotels,  colleges,  new-fashioned  asylums, 
&c.,  which  the  government  was  compelled  to  take,  for  hospital 
purposes. 

In  fact,  when  completed  with  the  ventilation  as  above  described, 
with  the  abundant  sunlight  on  both  sides,  without  any  obstructing 
partitions  and  abundantly  warmed  in  winter,  and  with  the  proper 
supply  of  moisture,  they  made  undoubtedly  the  most  comfortable  and 
wholesome  class  of  buildings,  as  3  whole,  that  have  ever  been  erected 
for  hospital  purposes,  not  excepting  even  many  of  the  recent  elabo- 
rately finished  buildings,  where  not  unfrequently  too  much  dependence 
has  been  placed  on  the  very  meagre  and  insufficient  effect  produced 
by  attempts  at  artificial  ventilation,  instead  of  relying  more  upon  the 
great  natural  means  of  ventilation — an  abundance  of  large  open 
windows,  open  fires  and  good  ventilating  stoves. 

The  ventilation  of  the  latrines  or  water-closets  of  a  hospital,  as 
well  as  any  other  place,  is  a  matter  of  great  importance. 

In  the  spring  of  1863,  I  had  put  up  in  a  hospital  in  Washington 
a  ventilating  shaft  for  the  latrine  room,  similar  to  the  one  .shown  on 
the  plans.  This  was  an  experiment,  but  it  proved  so  satisfactory 
that  it  was  subsequently  ordered  to  be  applied  in  all  the  principal 
hospitals. 

The  difficulty  in  the  isolated  wards  was,  that  it  required  a  sepa- 
rate fire  in  each  shaft  in  the  summer.  Where  it  is  possible  to  get  it 
near  the  kitchen  or  bake-oven  fire,  that  answers  a  splendid  purpose; 
but  in  the  single  wards  it  is  not  necessary  to  keep  up  a  constant  fire ; 
a  few  sticks  of  wood  every  morning  answer  the  purpose  of  keeping 
the  air  in  the  shaft  warmer  than  the  surrounding  atmosphere,  which, 
of  course,  creates  the  proper  draught. 

These  shafts  were  made  very  large — never  less  than  thirty  inches 
square  and  sometimes  three  feet  by  six  feet.  The  popular  plan  of 
opening  the  water-closet  windows  and  allowing  much  of  the  fresh  air 
to  enter  the  building  that  way  was  strenuously  avoided ;  the  windows 


56 

in  the  closet  were  fastened  shut,  and  then  the  air  to  supply  this  large 
exhaust  shaft  was  drawn  from  the  adjoining  ward  or  room,  which 
ventilated  that  ward  and  prevented  any  unpleasant  odor  from  the 
closets  returning  into  the  ward. 

Wherever  it  was  possible,  a  sheet  iron  or  cast  iron  pipe  was  carried 
up  into  the  centre  of  this  shaft  from  the  kitchen,  laundry,  bakery  or 
any  other  constant  fire,  and  where  no  heat  from  a  permanent  fire  or 
from  a  steam  coil  could  be  obtained,  a  small  stove  for  the  purpose  was 
provided. 

LEWIS  W.  LEEDS, 

Germantown,  Pa. 
7th  mo.  26th,  1867. 


The  subjoined  are  a  few  of  the  Letters  received  from,  prominent  Sani- 
tarians and  others. 


OFFICE  OF  THE  SUPERINTENDENT  OF  HEALTH, 

PROVIDENCE,  August  5,  1867. 
FRIEND  LEEDS. 

Tour  Lectures  on  Ventilation  have  been  received.  I  am  much  interested  in 
them,  and  think  the  views  given  are  correct.  I  hope  they  will  be  widely  circulated. 
Too  much  cannot  be  said  to  the  people  upon  the  subject. 

Ventilation  is  all-important.  Indeed,  I  think  that  if  the  air  could  bo  constantly 
kept  in  motion,  the  worst  sources  of  impure  air  in  our  cities  would  be  rendered 
almost  free  from  danger. 

In  seasons  of  epidemic  cholera,  the  most  oppressive  feature  of  danger  is  the 
stagnation  which  exists  in  the  atmosphere.  There  was  good  sense  and  true  philoso- 
phy in  the  old  custom  of  burning  bonfires  to  keep  off  disease.  I  must  close,  wish- 
ing you  much  success  in  your  efforts  to  awaken  the  people  to  tho  importance  of  this 
subject. 

Truly  yours, 

EDWIN  M.  8NOW,  M.  D., 

Superintendent  of  Health. 


BANGOR,  MAINE,  August  23,  1867. 
MY  DEAR  LEEDS. 

Your  pamphlet  was  duly  received.  I  have  read  it  with  much  interest,  and 
believe  it  to  be  worthy  of  extended  circulation.  It  is  the  clearest  paper  on  the 
subject  I  havo  yet  read. 

Tours,  in  haste,  A.  0.  HAMLIN,  M.  D. 


64  Madison  Avenue,  NEW  YORK,  Aug.  23,  1867. 
MT  DEAR  FRIEND. 

I  have  just  read  your  Lectures  on  "  Ventilation,"  and  I  am  very  much  obliged 
to  you  for  the  entertainment  and  instruction  they  have  given  me.  You  havo  very 
happily  hit  upon  a  stylo  which  is  neither  flippant  nor  dry.  I  am  sure  the  lectures 
will  be  read,  and  if  read,  they  will  do  a  great  deal  of  good. 

I  have  all  my  life  been  talking  and  writing  in  this  direction,  imploring  tho 
people  to  take  less  medicine  and  more  pure  air ;  and  I  feel  truly  grateful  for  the 
help  your  strong  shoulders  havo  given  me  in  what  has  thus  far  proved  to  be  a  labor 
of  Hercules. 


58 

Your  particular  method  of  ventilating  buildings  I  had  many  opportunities  ol 
proving  while  I  was  Medical  Inspector  U.  S.  A.,  and  I  assure  you  that  no  plan  was 
ever  more  simple  and  inexpensive— none  could  have  heen  more  effective.  Indeed,  I 
may  say  that  I  never  knew  it  to  fail. 

To  you,  therefore,  I  fully  believe  the  country  is  indebted  for  the  lives  of  many 
thousands  of  men. 

With  sentiments  of  esteem, 

I  remain  yours  truly, 

FEANK  H.  HAMILTON,  M.  D., 
Prof.  Principles  of  Surgery,  Military  Surgery,  Hygiene,  &c., 

Bellevue  Hospital  Medical  College,  N.  Y. 
Author  of  "Work  on  Fractures  and  Dislocations,  Treatise  on  Military  Surgery,  &c. 

L.  W.  LEEDS,  Esq. 


OFFICE  OF  THE  METROPOLITAN  BOARD  OF  HEALTH, 
No.  301  Mott  Street, 

NEW  YORK,  August  26th,  1867. 
FRIEND  LEEDS. 

Your  Lectures  on  Ventilation  have  given  me  much  pleasure,  and  have  renewed 
my  confidence  in  the  utility  of  popular  instruction  upon  the  subject.  I  heartily 
tbank  you  for  the  thoughtful  care  with  which  you  have  set  forth  all  the  essential 
principles  of  ventilation,  in  language  so  free  from  technical  words,  and  so  full  of 
plain  and  homely  illustration,  that  even  an  uneducated  reader  can  fully  understand 
all  you  have  written.  The  good  Dr.  D.  Boswell  Eeid,  Dr.  Wyrnan  and  myself 
had  each  attempted  to  use  such  a  style  of  explanation  and  instruction ;  but  you  have 
far  excelled  us  all. 

The  first  want  of  every  living  being  is  fresh  air,  and  unless  the  human  lungs  are 
supplied  with  such  air  constantly  at  the  rate  of  from  ten  to  thirty  cubic  feet  every 
minute,  by  night  as  well  as  by  day,  perfect  health  and  vigor  cannot  be  preserved. 
Then,  too,  there  are  exhaled  from  the  surface  of  the  body  and  from  the  lungs,  such 
quantities  of  ^waste  organic  matter,  which  tend  to  immediate  putridity,  that  it, 
together  with  the  carbonic  acid,  would  keep  the  human  body  immersed  in  a  deadly 
vapor  of  these  exhalations,  were  not  fresh  air  supplied.  The  illustrations  by  which 
you  have  made  these  truths  easily  understood,  are  admirably  given  in  your  lectures, 
and  the  method,  by  which  you  would  best  insure  success  in  removing  the  foul  and 
supplying  the  pure  fresh  air  in  every  place  where  persons  live  or  sleep,  are,  as  I 
believe,  from  my  own  careful  studies  of  this  subject,  most  correct  and  trustworthy. 
Indeed,  I  am  able  to  say  that,  in  my  examinations  of  the  vast  number  of  hospitals 
and  buildings  which  you  ventilated  during  the  late  war,  under  authority  from  the 
intelligent  and  humane  Quartermaster-General  of  the  army,  the  proof  of  entire 
success  in  your  work  was  everywhere  witnessed.  Simplicity,  invariable  certainty 
and  a  liberal  sufficiency  characterizes  these  admirable  methods  of  yours. 

I  wish  every  family  in  the  land  had  a  copy  of  these  lectures. 
Sincerely  yours, 

ELISHA  HAEKIS,  M.  D., 

Corresponding  Secretary  Metropolitan  Board  of  Health. 
To  LEWIS  "W.  LEEDS,  Esq. 


59 

VATJX,  WITHERS  &  Co.,  Architects, 
No.  110  Broadway,  NEW  YORK,  August  27th,  1867. 
DEAR  MR.  LEEDS. 

I  am  glad  to  receive  your  Lectures  in  printed  form,  and  trust  that  they  maj 
be  widely  read  throughout  the  community. 

Having  heen  in  the  habit  for  several  years  past,  of  consulting  with  you  profes- 
sionally in  regard  to  the  arrangements  to  be  made  for  heating  and  ventilation  in 
plans  for  public  and  private  buildings,  I  take  this  opportunity  to  acknowledge  the 
value  of  the  aid  thus  given ;  and  as  I  feel  assured,  from  a  lengthened  personal 
experience,  that  your  thorough  knowledge  of  the  subject,  both  theoretically  and 
practically,  is  calculated  to  render  your  assistance  particularly  valuable  in  the 
adjustment  of  complex  and  intricate  plans,  I  trust  that  one  result  of  the  circula- 
tion of  your  interesting  pamphlet  may  be  to  introduce  you  more  widely  to  members 
of  the  architectural  profession. 

I  remain,  Dear  Mr.  Leeds, 

Tours  faithfully, 

CALVEKT  VAUX. 
LEWIS  W.  LEEDS, 

Heating  and  Ventilating  Engineer. 


110  Broadway,  NEW  YORK,  Aug.  30th,  1867. 

Mr.  LEWIS  W.  LEEDS  was  employed  early  in  the  war  of  the  rebellion  by  the 
Sanitary  Commission,  as  an  agent  to  urge  the  necessity  to  the  health  and  strength 
of  the  army,  of  the  thorough  ventilation  of  tents  and  quarters,  and  to  devise  and 
suggest  to  the  proper  officers  the  adoption  of  the  best  means  for  this  purpose. 

At  a  later  period  of  the  war,  at  the  suggestion  of  the  Commission,  the  Quarter- 
master's Department  engaged  his  services,  and  gave  him  large  discretionary  powers 
for  the  ventilation  of  hospitals.  He  was  thus  employed  during  all  of  the  war,  with 
great  advantage,  and  the  improvements  which  he  brought  about  were  unquestion- 
ably the  means  of  saving  thousands  of  lives. 

Mr.  Leeds  has  a  special  talent  for  making  improvements  in  houses  of  ordinary 
construction,  by  means  which  may  bo  readily  adopted,  and  with  materials  which 
may  be  anywhere  procured  without  difficulty  or  great  expense. 

Mr.  Leeds'  course  of  lectures  on  Ventilation  is  calculated  to  supply  instructions 
of  great  practical  utility.  'An  invaluable  addition  to  the  health,  happiness  and 
wealth  of  the  nation  would  result,  if  they  could  be  delivered  before  every  school 
in  the  countrv. 

FEED.  LAW  OLMSTED, 
First  General  Secretary  of  the  Sanitary  Commission 


TREASURY  DEPARTMENT, 

Office  of  the  Supervising  Architect,  Sept.  llth,  18G7. 
MY  DEAR  FRIEND. 

Your  valuable  Lectures  on  Ventilation  have  been  received,  and  have  been 
read  with  much  pleasure,  more  especially  as  you  are  about  the  only  person  I  have 
ever  met,  who,  after  making  the  ventilation  and  heating  of  buildings  a  specialty, 
has  condescended  to  follow  the  laws  of  nature,  and  provide  the  means  of  adapting 


60 

them  to  our  artificial  modes  of  life.  Your  lectures  show  a  thorough  study  and 
knowledge  of  the  principles  involved,  which  are,  like  all  natural  principles,  very 
simple  if  once  understood.  I  have  also  to  take  this  means  of  acknowledging  the 
valuable  aid  that  I  have  received  from  you  on  many  occasions,  and  to  express  a 
hope  that  you  will  not  despair,  hut  relying  on  the  adage  that  "truth  is  mighty" 
&c.,  go  on  with  your  exposures  of  the  absurdities  of  the  complicated  and  costly 
humbugs  that  are  so  fashionable  at  present,  and  trust  you  will  succeed  not  only  in 
your  missionary  labors,  but  find  them  pecuniarily  profitable. 
Very  respectfully, 

A.  B.  MTJLLETT, 

Supervising  Architect 
LEWIS  W.  LEEDS,  Esq., 
Engineer  Ventilation  and  Heating, 

Germantown,  Penu'o. 


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